# Harrison L5 Metalworking Lathe (1950) Teardown & Overhaul



## Sideways (6 Jan 2022)

These machinery overhaul threads can take a while if posted up in real time. Life often gets in the way and plays havoc with our good intentions.

This thread will hopefully be of interest to a few folk and has the advantage that the work is essentially done as I start to post so it will only take as long as it takes me to post pictures and tell the story. The action takes place in the workshop of my good friend Deema who generously shared his space and know-how along the way. He was doing a similar overhaul on his own J&S 540 surface grinder while I tackled this rather simpler project. We tried not to mix up the parts ....

The machine in question is an early Harrison metalworking lathe. Made in Yorkshire in 1950 based on the serial number, I'm told it spent most of it's life in a training school of some sort before I became the second private owner. It's a gap bed lathe, turns 9" diameter not including the gap. It has an 8 speed spindle from 21 to 480 rpm and cuts threads courtesy of a heap of change gears and a three speed gearbox.

I've used lathes several times over the years but never owned one before. The L5 is old and slow, but strongly built and heavy. It's also, just, small enough to shoehorn into my garage.

The L5 includes a one piece cabinet base made from heavy plate. The manual says they weigh 560Kg all up and it felt like it. It was a monster to load into a Luton van even with two hydraulic pallet lifters to support a tail lift which was nowhere near strong enough to raise it.







Back in Deema's workshop, it looked very promising. Relatively clean, simple and strong.











We had seen the machine working and the immediate priority was to sort out the electrics so that the lathe could be properly checked.. A massively oversize 4kW 3ph cast iron motor had been fitted at some point in it's life driven by a 1.5kW VFD which was literally kicking around the floor on a metal plate. These needed to come off, motor stripped, cleaned, bearings renewed as routine and a new, properly sized VFD fitted.

Life was to prove much more complicated than that ....


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## Sideways (6 Jan 2022)

The motor that came with the lathe was a fine, British made, item but hadn't been properly connected. Thanks to the cables being taken into the top of the terminal box with no gland to seal it, I was able to tip half an eggcup full of brass turnings out of the inside of the motor. Surprisingly this hadn't damaged the windings though both the armature and stator carried a few scratches from brass between the moving surfaces. I dislike painting over a painted motor so a deal of time was spent with a wire wheel stripping it back for repaint, then new bearings and reassembly. Sadly after all that work the motor ran well but with a little more vibration than I wanted. I decided to replace the motor so it was primed, boxed up and sent to a new home. In excess of Hermes's 20Kg limit the postage cost rather a lot.













The replacement was a little used top quality ABB 4 pole 2.2kW motor.




Many Harrison lathes hang their motors simply on the back of the machine using sliding brackets. These are a cast part and not exactly flat.
They went on the mill and had the slots, top surfaces and feet milled flat straight and square.








The motor mounted nicely but the spindle only just cleared the end cover so two lengths of tube were drilled and tapped to serve as stand offs











Much better. A new motor with a metric shaft required a new pulley. This is a taper lock type by Dunlop. Three rather long thin belts are used. The upper pulley is original and imperial, but I found that a metric SPZ profile is a close enough fit that the motor pulley and belts in that profile would work happily with the original upper pulley.










Ebay provided a good 2.2kW VFD to match the motor and we were ready to spin it up.


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## Sideways (6 Jan 2022)

The headstock has a filler and oil level gauge on the back side of the head. The oil level looked to be well below minimum so the headstock gears needed checking.




4 obvious capscrews and the alloy cover is easily lifted off from in front of the speed selection levers on top of the head.









Oil was thick and dark in the bottom, barely enough to actually drain out of the plug on the sight gauge.
I consulted with my buddy and we decided the best way to flush it would be to pour in a litre of diesel and run the motor gently.

This was repeated a few times, draining and replacing the diesel with rounds of brushing around all the gears, the inside of the head and copious amounts of good blue paper to remove the metal fragments that had probably accumulated inside since the machine was made.

As it came cleaner, I put several rare earth magnets around the inside of the head to collect swarf from the gears and this worked well to pick up the fine black stuff.




Running the motor on a variable drive is ideal for this type of experiment. You can gradually increase speed and watch how the splash lube works.





Your browser is not able to display this video.




Although the gears showed signs of burring at the edges (ham fisted selection and possibly attempts to change gear before the spindle had stopped) nothing looked or felt too bad for a lathe that's older than I am.

I ordered up some oil for the head and the slides while the diesel was having a good soak and 3 days after first opening it up, I drained the head and put in the oil.

Filled to the top line, the oil isn't very deep in the box. All the lubrication relies on just a few larger gear wheels dipping down into the oil and throwing it up for everything else. Oil thrown onto the inside of the head drips down onto a ledge around the top cover, runs around and tops up a hollow above the main spindle bearing. From here it simply pours down a hole into the two big angular roller bearings at the front.
One clear lesson from this is that when starting the lathe from cold, it's important to get that splash lubrication running to get oil into the main bearings. Don't just start the lathe and put it straight to work in low gear. Run it for a couple of minutes in one of the top ranges first to get the gears and bearings properly lubricated.

Gear selection on the L5
Back in the first post, there's a picture of the speed selection chart on the top of the lathe. It's confusing until you know how it works.
Spindle speed is done with 3 levers.
On the FRONT of the head is a big lever than shifts between pointing at 10 o'clock and 2 o'clock. This selects high or low range represented by the yellow and red numbers on the speed table.
On the top there are two small levers pointing towards the operator. Each has 3 positions. Left and right select actual speeds. Middle is a neutral. There's an interlock so that you can never try and select a speed with both levers at once. In order to move a speed lever left or right to choose a speed. The other lever must first be put in the middle position. Left lever selects between the two low speeds in each range. Right lever selects between the two high speeds.
It's actually easy once you get used to it.
The gemlin waiting to bite you is that the combined clutch brake lever that applies power is on top with the gear selectors. The lever closest to the operator and the one you instinctively want to grab in a panic is the high / low range selector which mustn't be moved when the lathe is running. I wonder how many apprentices got that wrong at least once  

The standard L5 came fitted with a 6 pole motor (just under 1000 rpm) that gave a speed range from 21 to 480 rpm.
It was also available with a 4 pole motor and a twin speed (2 or 4 pole motor). Depending on the motor that gave top speeds up to 720 or 1440 rpm. very low by the standards of today where lathes may hit 3000 rpm or more to turn smaller parts with replaceable insert tooling.

With a 2.2kW 4 pole motor I have plenty of power available and the variable speed option. I've configured the VFD to spin the motor faster than it's design 1400 rpm. 4 pole motors are physically almost identical to 2 pole, so there will be no mechanical reason that it can't take 2800 rpm if I wanted, but when the lathe was sold with a 2800 rpm motor, it was also given a second bearing on the tail of the shaft. I won't try to go that fast. My setup will allow maximum power upto 720 rpm but thanks to the VFD can be increased to 1000 rpm at reduced torque for light cuts.

21 rpm low speed feels SO slow !


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## Sideways (6 Jan 2022)

Having seen inside the headstock and actually cut metal, I decided that this really was a lathe that I'd like to keep for a while.
I decided that I wasn't brave enough to strip down the head when it didn't seem to need it, but peering around and underneath the saddle it was clear that most everything else would need to be stripped for a serious clean.

The previous owner hadn't used the lathe much I suspect and when he had, it had been to make small parts, turned dry from brass. The lathe was full of brass shavings - they get everywhere - and the whole machine had ben wrongly lubed with thick grease. The L5 and several of its successors have several grease nipples but they aren't. In fact they are oiling points and should be regularly lubed with a push type oiler.

Here are some images to show what was lurking inside the saddle and apron once we got them off ...

The apron seen from above and behind





Looking down into the apron - front control handwheels at the top edge of the photo





The split nut that opens and closes on the screw for screw cutting





This mechanism is the surfacing feed.





I later learnt that removing the saddle and apron of the lathe should be easy. The bearing block at the right hand end of the two long shafts (one slotted, one threaded) is unbolted, some pins removed and then the two shafts can be drawn out through the apron, to the right of the lathe.
This worked great for reassembly once everything was cleaned. During the teardown, everything was so dirty that this wasn't obvious and I just removed bolts and tapped out pins wherever I could get at them. Eventually parts becoming loose enough to wriggle free of the bed.


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## Sideways (6 Jan 2022)

The L5 turned out to be easy to disassemble. Shafts were mostly steel running directly in the cast iron or occasionally in a bronze sleeve in the casting. Shafts were held in place either by grub screws that only needed an imperial allen key to remove, or in many cases they were pinned using a gentle tapered bore and a tapered pin. These lock securely enough but are easy to tap out. They have the advantage for maintenance that there is a right and wrong way to line parts up. It is more difficult with a sprung roll pin because unless carefully checked beforehand you may get one of the two parts being pinned 180 degrees out and start driving the pin only to have it stick and need driving out again.






Despite the grime, only one significant problem turned up. One of the large gears in the apron involved in the power feed had a tooth completely missing. Presumably a user crashed the tool into the work or chuck under power at some point and the tooth was the thing to shear off.

The next stage of the overhaul was a massive clean up taking several weeks off and on.

Weapons for this included Gunk degreaser (cheap) and Jizer (expensive but much better, about as good as diesel but without the stink and 5x the price).
Wire brushes, scotchbrite pads, electolytic rust removal and most useful, an improvised tank to do the cleaning uin.
I bought some large army surplus stainless steel catering trays and these were very helpful - it was like having a large sink to do the dirty work iin and the holes in the trays allowed the grit to drop through into a heavy bin bag sandwiched between two of these nested trays.






Eventually, a clean kit of parts emerged





These had to be kept clean while the adjacent lathe and mill were put to use repairing the broken gear


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## Sideways (6 Jan 2022)

Gear repair:

There are a number of ways of repairing or making a new gear. The gear I needed to fix or replace was about 4" diameter and 42 teeth. It was an imperial size and after reading around and taking measurements, I was confident I knew what the tooth profile was and bought a milling cutter capable of replicating it for about £25 from RDG.
I also bought two cast iron blanks in case I needed to machine a brand new gear from scratch. One to use. One to mess up. A 5 inch cast iron blank, one inch thick, cost about a fiver plus £5 postage last year.

Nonetheless the gear was in decent condition apart from the missing tooth and I wanted to try out a repair where a new piece of steel is silver soldered into a closely fitting pocket milled in the gear, then the tooth is recut by horizontal milling.

A tightly fitting silver soldered joint is reputed to be nearly as strong as a brazed joint but needs less heat to achieve it.

The process worked well and I'm really pleased with the end result.

First, a robust arbor needs to be turned from a bar end to hold the gear for milling. This has to be a tight fit in the bore (zero play) and threaded so that it can be clamped tight with a nut.
The spindle is then mounted on a mill between a dividing head with horizontal chuck and a fixed centre, and a pocket cut out where the broken tooth was.










A piece of steel was prepared that was a tight fit in the cutout.
The gear was setup on edge between fire bricks to try and keep the heat in the gear with as little loss as possible





The joint was fluxed and silver solder placed on both sides where it could wick into the joint. 2 torches with mapp gas provided the heat and it took less than a minute to reach the 700 degrees C needed to melt the 55% Ag silver solder





After cooling, the gear goes back on the horizontal mill, this time with the gear cutter mounted.
It took much longer to position the job than it did to cut it. Two cuts need to be made, one taking away each flank of the tooth blank, with the aim of getting the correct shape, depth, height of the new tooth, perfectly spaced between the adjacent pair.





Several passes are made cutting deeper until the correct depth is reached, then index the gear around and cut the other flank to the same depth. 
Guessing the depth is a challenge as the new tooth is too tall and looks narrower than the others. The tooth is taken down afterwards on the lathe but meantime, it's all about judging the bottom of the cut.





Mill off the excess length, shorten the new tooth to the same length as the others on the lathe then carefully hand file the ends of the new tooth to match the others

















It's not perfect, I should have milled 0.1mm or so deeper, but I'm very happy for the first time of trying a number of these steps. The joint is very sound.


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## Adam W. (6 Jan 2022)

It's very tidy work and well executed. Will the small voids in the silver solded present a problem at all ?


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## Sideways (6 Jan 2022)

Reassembly is the reverse of taking it apart so skipping many photos which I'm happy to share if anyone has questions. Here's the cleaned and reassembled apron with the repaired gear installed. The apron manages the left right travel of the cutter both by hand and under power for surfacing and threading.
This is the back and the apron is upside down, so that you can see the split nut that engages the feed screw (towards the R), and the small pinion gear (lower L) that engages with a rack along the side of the bed for manual feed and for surfacing under power.


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## Sideways (6 Jan 2022)

Adam W. said:


> It's very tidy work and well executed. Will the small voids in the silver solder present a problem at all ?


I don't think so. Certainly not so far. The other end of the tooth is a tighter fit so I hope that porosity doesn't go too deep. The ones that you see in the gullets of the teeth are just on the surface because I didn't mill down quite far enough to remove them completely.

Fingers crossed ....


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## wallace (7 Jan 2022)

Thoroughly enjoyed that, I think when I get a metal lathe it will be a harrison, I've been watching doubleboost that long I feel I know the lathe quite well. I have a dinky little drummond that I started but got sidetracked by wadkin lumps. 

Deema's place looks like a cracking place to play, with some useful bits of kit.


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## Sideways (7 Jan 2022)

Saddle, slides and gearbox still to come Wallace. Hope you enjoy a long read  
I don't know if pictures of the insides of things count as helpful or should come with a spoiler alert !

There's huge advantage from having a like minded buddy to work with. One part of that is you tend to encourage each other to "just have a go". Once we start, we can usually fix it or maybe break it and have to make another


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## Tony Works Wood (7 Jan 2022)

Great job on the overhaul, very thorough. That gear repair is superb. They are great lathes, I fitted a faster 2HP single phase motor to mine as well. It was my first lathe and was also dated 1949 I checked it with Harrisons in about 1985 with the serial number after I bought it when I rang them up to enquire about a manual for it and a drawing for spindle nose dimensions. They sent me both free of charge. I sold it about eight years ago when I bought a later model Harrison 140. Looks like I got one of the last of the Mk2 design and you got one of the first of the Mk3 design sold in the same year lol. The pic is when I sold it. Looking forward to the rest of the overhaul.


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## Sideways (8 Jan 2022)

Excellent Tony. Thanks  
Yes, I believe mine is an L5 mk3 and yours is slightly different though v similar.
Hope you are enjoying the 140. The L5 is a proper lathe with a useful capacity but it's strange to have the same 1.5" 6tpi threaded spindle on a metal lathe as they used on the graduate wood lathe !
Your newer 140 is nice step up the range !


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## Fergie 307 (8 Jan 2022)

Nice job. Are you a member of the Harrison lathe owners group? I and other have posted extensive details on there regarding the stripping down and repair of every aspect of this machine, which you will find useful. The big old motor fitted to yours was a n option when new. A common problem with these is the clutch, or specifically wear in the pins, worth checking and an easy repair if needed. You also want to carefully check the state of the friction surfaces on the brake, they can sometimes wear right down. Mine is a 1961 5A. The second picture is of the magnetic sump plug I added to mine to catch any particles. In the trough over the main bearing feed hole you should hopefully have a very fine mesh gauze, intended to trap anything that might otherwise find it's way into the bearings. Good luck with the rest of it, if you get stuck with anything then only too pleased to help. The owners group is well worthwhile, and a good source of spares too like your gear, although you have made a nice job of repairing it.


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## Fergie 307 (8 Jan 2022)

I would urge you not to take the headstock apart. The spindle and associated parts are all dynamically balanced and have to be kept in the correct orientation. It's an easy enough strip down but putting it back together again correctly is another matter, so unless there is something specifically wrong with it I would leave well alone. When you get to the saddle you will find there is no adjustment for the mounting strips which hold it on the bed, one long one at the back and two short ones at the front, the right hand one of which also acts as the saddle lock. If there is play between the saddle and bed this is usually down to wear in the strips. These are deliberately made of fairly soft iron. The fit was adjusted at the factory by scraping the underside mounting area on the saddle casting itself, the strips being completely flat. The beauty of this arrangement is that to restore the original clearance all you usually have to do is to regrind the strips themselves flat to remove any slight step worn in them where they run on the underside of the ways. Have fun.


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## Sideways (8 Jan 2022)

Excellent insights Fergie. I didn't know those details.
My L5 doesn't have the mesh filter you mention or marks from having had one, but there are now a dozen flat neodymium magnets around the inside so I'm onboard with that method.
My big motor that I removed wasn't an original. It was 1980's, pre owned but not vintage 
Your L5a looks great. Very clean, better gearbox and I like the splashback.
I'm registered for the groups.io Harrison mailing list which is mildly helpful but very limited because it doesn't intend to be a forum and has v limited space for image storage.
If there's another forum I'm unaware of it. I don't do facebook in any shape or form so if there is something there, I'll have to do without.
Please continue to advise and point out my mistakes as I post the rest of the cleanup !


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## Sideways (8 Jan 2022)

Here's the gearbox:

The L5 is available with either this simple 3 speed version or a better Norton gearbox with more ratios. The 3 speed has 1 : 2 : 4 (or 1/2 : 1 : 2 ?) relative speeds and after cleaning up the apron, it seemed lazy not to strip and clean it. It bolts straight through onto the front of the headstock. The drive comes in at the left hand end via the change gears, and it drives the two long shafts from its right hand end.

No synchromesh here. Change gear when the lathe is stopped.
Lube is via oiling nipples on the front, on the two output shaft bearings and importantly, one on the left, inside the changewheel case and obsured by the lower of the 3 changewheels. This is why it can be a good thing to have a list of lubrication points and tick them off as you go. Here's the input end:







Once unbolted, the back of the gearbox is open and the mechanism simple










Points of interest. The lead screw (upper output shaft) is only used for threading. It doesn't need to be turning most of the time so the L5 has a simple sliding dog clutch that can be slid 1/2" left or right along the shaft to engage and disengage the lead screw from the gearbox. Quite neat.

To reduce the damage in case the operator loses attention and crashes the tool while surfacing under power, there is a spring loaded clutch inside the thick stubby shaft on the lower left of the gearbox in the pic above. This should prevent an accident stripping teeth in the gearbox, although as we saw, it didn't prevent a tooth being lost inside the apron.
Here you can see inside that mechanism.










The upper shaft of the gearbox is partially keyed. Gears basically thread on and where necessary are held in place with taper pins through the gear and shaft.
Kindly, the gears were already stamped making assembly a case of pairing the numbers.






To select gear, the cluster of 3 gears on the lower shaft is simply moved between left, centre and right by a fork attached to the gear selector spindle.





All the bearings in the gearbox are plain. No ball bearings. Steel shafts run in bronze bushes.

Here's the output end of the gearbox after refitting. The clutch for the feed shaft is below and the socket for the screw is above, showing the drive dogs ready to mate with the selector.





And from much later in the reassembly, this is what it looks like with the shafts refitted and the sliding dog clutch engaged (this has a spring loaded ball bearing to keep it in the chosen position and the key is PINNED, which makes it quite a challenge to remove !











Overall the gearbox was simple and just needed a good clean. The spring loaded clutch and dog clutch were interesting to figure out. Reassembling the spring clutch involved compressing the spring inside so that one (two ?) tiny countersunk capscrews could be screwed home to hold it together. On the feed screw, the inch long piece of key steel that transfers the drive from the sliding dog to the shaft has a pin through it, and that all needed flattening and filing as this wasn't obvious and I had bent it trying to get it out.
The numbered gears and use of taper pin meant that the reassembly of the gears was very straightforward. But it still makes sense to photograph EVERYTHING as you take it apart ....

Next up will be the saddle and slides


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## Spectric (8 Jan 2022)

A good old solid machine, they were common in the school metalwork shops and found in many workshops in the days when we had large manufacturing in the UK. The gearboxes were better made than what you find on modern cars.


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## Sideways (8 Jan 2022)

Saddle and cross slide

Back in 1949 this lathe would have been made in imperial. I received it with metric dials fitted and I assume that in it's life as a training lathe, it would have been converted some time before or after decimalisation. The gearbox and changewheels allow either imperial or metric threads to be cut depaending on the combination of change gears, but converting the dials would mean new screws and nuts in the slides.

Firstly the saddle. The L5 mk3 doesn't have hardened ways. just cast iron on cast iron. The larger section on the L is to the front and the apron with it's gears hangs from this.





A good clean was needed and at some point, wire brushing the scarred paintwork on the top of the saddle turned into a full strip of the paint and re dressing the casting to remove the worst of the grind marks etc left after manufacture. Using a blue Norton vortex blending disk I cleaned up the saddle and although the casting wasn't perfect, I decided that I was going to leave the top surfaces bare.

Lathes always get scratched up after a while from brushing away the swarf so I decided that this was going to be maintained steam punk style from now on. Wiped down with an oily rag and covered when not in use.





In the image above you see that the cross slide slides on dovetail ways and that a tapered gib (cast iron or steel) is used to take up the play and give a good sliding fit. Two large chrome headed screws set the position of the gib strip to keep it snug and to stop it wedging itself even tighter.
The wear is at the limit of what's usable. I need to make a new screw for the back as there isn't enough thread to let me use the last 1/4" of adjustment left in the gib.
These are a carefully matched taper so making a completely new gib will be a challenge best done with Deema's surface grinder once he finishes that rebuild, and we both need to learn to scrape these in. That will be a big month when the time comes.

The cross slide screw looks in good condition.




The brass nut is a nice fit and has a slot so that it can be tightened to take out backlash as it wears. This is interesting. It isn't the original L5 imperial nut. In fact I think it's a nut from a later model L6. The L5 mk3 wasn't made with a split nut and this is a clue to the metric conversion.

The cross slide screw simply slides into a plain bore in the cast iron of the saddle.
A disc is screwed on to provide the index mark for the graduatel dial, then a sleeve slides over the shaft and is secured with a taper pin. This is filed flush with the sleeve.
There are no special baring surfaces at all, just steel on steel or cast iron and some holes above to allow oil to be dripped into some of the sliding surfaces.















This isn't a sophisticated arrangement, so we decided to improve it by machining the index plate and adding a slim roller type thrust bearing.
After some careful measuring and lathe work because there's no facility to adjust clearances to add or remove axial play it turned into this. A satisfying mod !


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## Sideways (8 Jan 2022)

Saddle and slides 2

Here you see the cross slide nut as the lathe was received. A simple round boss (round tenon) on the nut fits snugly in a blind hole in the underside of the cross slide. A countersunk screw keeps it in place and allows it to turn to align with its lead screw.









Unfortunately, the lathes must have been hand fitted when made, and this wasn't done correctly when the replacement metric screw and nut were installed.
As the cross slide was wound in and out, the nut would run freely then bind as it came closer to the front.
We measured and found the nut was offset to one side and wasn't in line with the screw. As the screw was snugly fitted in a long hole at the handwheel end, it was nicely aligned in the saddle, but the mounting boss on the metric nut was offset about 1.5mm to the side compared to the hole it needed to fit in the cross slide. The closer it was wound forward, the more it tried to bend the screw and eventually jammed.
I think the lathe must have been like this ever since it's metric conversion. The only way to make it work at all was to leave the gib sloppy and use only the far end of it's travel (small parts).

The nut was otherwise good and a replacement would guarantee nothing, so we devised a fix involving a top hat insert with an eccentric bore so that the lateral error could be dialled out. Dimensions allow about 2mm of sideways adjustment. This was enough with a bit to spare and it worked well. You need a lathe and a mill to fix either of these tools but it made another good day  


























Once done, the cross slide could be wound fully forward and back without binding


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## Sideways (8 Jan 2022)

Saddle and slides 3







With the cross slide mods complete, I made a new sheet steel insert to cover the front of the screw, thinning a section immediately above the gear on the left as clearance is very thin. This plate is removable so that I can slide it forward to access the oiling hole for the screw's plain bearing, but keep that covered otherwise.

The bed was cleaned and the rack removed for cleaning then replaced










Then refit the slide, bolt the apron back on, thread the two shafts through the apron and reseat them in the gearbox.















Finally bolting the right hand bearing block in place.


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## Sideways (8 Jan 2022)

Compound slide

Nothing complicated here. The compound slide screw and nut were in good condition. A good clean and stripping back to my chosen bare metal look for the parts that are going to be scratched by turnings. I can't remember now whether I cleaned, or replaced the thrust bearing on the compound slide ! Senior moment ...

Note that the L5 with just 9" swing is pretty simple up top to keep the slides as low profile as possible. The 11" capacity L5A and other models that followed it had a thicker cross slide with T slots that allow the compound slide to be completely removed very easily. 

Here it is fitted and with an oversize quick change toolpost sitting on top.






The compound has two castings, lower with a round boss to anchor it to the cross slide and let it rotate










Upper has a fixed screw that the chosen toolholder drops onto and is then bolted down.









The slides between the two are dovetail again but the gib is plain not tapered with set screws to adjust the play

The feed screw and split nut are similar to the one on the cross slide, but simpler and no problems were found this time











There are two thrust bearings this time and bigger. The photo above shows the parts lined up in sequence for reassembly
Here is the front end of the screw. index plate bolted in place, sleeve pinned and ready for the dial to be slipped on and the handwheel fixed with a taper pin.


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## Fergie 307 (8 Jan 2022)

Sideways said:


> Excellent insights Fergie. I didn't know those details.
> My L5 doesn't have the mesh filter you mention or marks from having had one, but there are now a dozen flat neodymium magnets around the inside so I'm onboard with that method.
> My big motor that I removed wasn't an original. It was 1980's, pre owned but not vintage
> Your L5a looks great. Very clean, better gearbox and I like the splashback.
> ...


it is the io group I was referring to, as you say not a forum and with limited space. Lots of knowledge amongst the members of all Harrison machines so if you run into a problem then there will usually be someone who knows the answer.


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## Fergie 307 (8 Jan 2022)

Oh and the metric dials and screws are most likely from a 5a. These were made as a sort of hybrid with imperial leadscrew and gearbox but metric top and cross slides, Mine is configured in that way. Many parts are interchangeable between the L series machines. Some very according to size so a n L6 has a wider bed and and saddle and the screws are longer. Having said that the 5a screws ought to be a straight swap, s I doesn't explain yours being off. Like your solution though, ingenious.


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## Sideways (8 Jan 2022)

Tailstock

The L5 tailstock is MT2 taper, graduated, and inludes a feedscrew and pin. This means that it doesn't rotate as you wind it out with the handwheel.

There is nothing complex about the construction. Just a need to pay attention to the locking lever. This is cam action and needs to be adjusted to have it lock with the lever in the right position.

Note that alignment of the tailstock is done with a combination of adjusting screws and shims. I haven't done a full alignment on mine as I don't have all the kit I need but the process includes turning a test bar between centres and then clocking the cuts to look for taper which would indicate misalignment. 

The head of the lathe is bolted down to the bed and doesn't include any special provision for aligning it as on more modern lathes. To test the alignment of head and tailstock bores I believe that you need ground test bars in MT2 for the tail and MT3 for the head.

Here are the teardown pictures of the tailstock

Lower casting and parts










underside





With the cam lock inserted





Lower portion that slides on the bed - upper side here that mates with the body of the tailstock (above)





And with the shims replaced as they were before dismantling





Here is the shaft


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## Fergie 307 (9 Jan 2022)

To check headstock alignment you ideally want a ground test bar mounted on the end of the spindle but not supported at the other end. Run a dti along it mounted on the toolpost. You can also do a cut across collars. I use an inch diameter CDS tube about 18 inches long with two Delrin collars, each about 10mm wide and 40mm in diameter. One collar wants to be at the end of the tube, the other about a foot further down. Mount the tube in a chuck so one collar is close to the front of the chuck, do not support the other end of the tube. Take a light cut with a very sharp HSS tool by just running the saddle down the bed across the faces of both collars. Now measure them with a micrometer, calipers aren't really accurate enough. Ideally both collars will be the same size, if not the difference will tell you how the head is misaligned. Beauty of this method, or Rollies dad's which is similar, is that it will not be influenced by any inaccuracies in the chuck. Using the delrin collars avoids push away influencing the result as may be the case of you do a cut in steel. Very important to ensure that your saddle or slides are not moving about, so should be done with cross and top slides locked. and check carefully for any movement in the saddle. Also important to check there is no excessive play in the spindle bearings. If you do find the head is off then the usual way of correcting it is to loosen the mounting bolts and then insert shims of appropriate thickness between the flat sides of the headstock casting and the mating face of the bed, you will see where I mean. If you are lucky and the adjustment required is very small you may find you can get away without shims. It's a frustrating job as you can get it perfectly aligned by as soon as you torque up the bolts it will move again, so you tend to have to have several goes at it. usually it's a case of noting how much in moves when tightened up, then overcompensating by that amount so that tightening it up pulls it into line, if that makes sense. You are ideally aiming for a figure of 0.01mm or less difference between the collars. This is perfectly achievable with patience.


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## Sideways (9 Jan 2022)

I like the delrin collar around tube idea. As you say, cuts in steel with a long stick out can be affected by flex in the bar. Having sacrificial plastic to take text cuts off sounds like a neat alternative.
Cheers


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## Fergie 307 (9 Jan 2022)

Easiest way to check for play in the saddle is to mount a dti on the flat of the rear bedway, a mag mount is ideal. Rest the pointer on the upper rear machined face of the saddle. Now use a piece of 4x2 or similar, suitably padded and insert it between the chip tray and the underside of the apron casting. Lever gently and see if the dti moves. if it does then this indicates too much clearance between the rest of the saddle and the bed, so The saddle is effectively see sawing on the front way. Very probably caused by a worn rear mounting strip, but can befriend to wear on the underside of the saddle itself.Repeat the rest with the dti on the front way. If this gives movement Then you have worn front mounting strips, or wear in the front way or it's matching surface on the saddle. there is really no definitive figure for how much play is acceptable. A Good guide is to run the saddle up and down the bed. If it runs very freely, with no resistance, then it is too loose. There should be a discernable, if slight, resistance. Good idea to do these measurements at the tailstock end first, where the bed is likely to have little wear, and repeat with the saddle near the chuck, the part of the bed most likely to be worn. Any significant difference in the readings at either end is an indication of bed wear. 
Hope this is helpful.


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## Fergie 307 (9 Jan 2022)

Sideways said:


> I like the delrin collar around tube idea. As you say, cuts in steel with a long stick out can be affected by flex in the bar. Having sacrificial plastic to take text cuts off sounds like a neat alternative.
> Cheers


You can either bore them very accurately and make them a push fit, or stick them on with superglue doesn't really matter. CDS is Good because it tends to be pretty accurately sized and is very stiff but light so you don't get droop coming into play owing to it falling under its own weight, as you can with a solid bar. If you don't have a ground test bar, have a look to see if you have a gearbox reconditioner near you. They will probably sell you an old layshaft for next to nothing. May have been replaced owing to bearing wear, but still a nice precision ground bar which can be very useful mounted between centres for checking tailstock alignment for example.


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## Sideways (9 Jan 2022)

Light relief - roller skates

At 560 kilos, the L5 isn't that easy to move. In my garage, it will sit back to a wall in a corner. Anticipating the challenge of rolling into place and then having a means of pulling it forward from the wall if I need to do maintenance on the motor, I made up a pair of skates. They should be good for close on 2 tons the pair so ample. They are fabricated from hot rolled channel and the rollers are sold as spares for renovating pallet trucks. They have ball bearings and solid plastic tyres that avoid damage to the floor.

Everything is self evident here. There were just some largish holes to drill - dead straight - axle pins to turn from mild steel and spacers to keep the rollers centred in the channel which I'd bought as an offcut. Holes were drilled on the mill as it's stiffer than even a good pillar drill.










The length of the C section spans the lathe's base front to back so these are easy to use once the base is lifted high enough to slide under.













The mild steel got some metalguard to slow down the inevitable but unimportant rust. The channel was wire brushed, heated with a gas torch and then wiped over with linseed oil. It makes an easy finish which lasts 1-2 years against the winter damp in the shop.

In normal use, the lathe sits on 4 adjustable anti vibration feet. The stiffness of the base is ample to keep the lathe happy. It doesn't need bolting down, just levelled side to side and front back.


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## Fergie 307 (9 Jan 2022)

If you look at the pic of mine I have done much the same. I needed to lift it as I am very tall. The legs you see it standing on are cut down scaffold feet. These can be unbolted and swapped for five inch castors when the need arises, makes moving it around a doddle.
Oh and while I think about it, bed wipers. The felt ones tend to be pretty useless, the swarf just gets stuck in them and dragged up and down. I couldn't find anyone selling suitable plastic ones when I rebuilt mine. I got some 5mm thick leather from my local saddler. Easy to shape, and once they are on they soak up the oil and swell to give a nice tight fit, and spread the oil. They also seem to be too dense for stuff to get stuck in them. I think you can get plastic ones now on e bay, those for a 140 should also fit. Looks like you are doing a grand job. Lovely old machines and built like a tank.


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## Sideways (9 Jan 2022)

I found a chap on ebay selling 3D printed ones for a variety of machines. I've fitted a set of his. 

Clutch and brake:
The L5 has a spring loaded clutch and brake concentric with the upper pulley driven by the motor V belts.





In the first image, you see it top left. Down and right is a hollow shaft which is the main spindle. The spindle bore on an L5 is small. Under an inch. I won't be feeding any two inch bar stock through the head on this. In this picture, the change wheels are removed so that you can see behind them.

Following are simple pictures of the component parts once the round nut at the end of the black spring is unscrewed and everything unthreaded.
Tightening the nut increases preload on the spring makes it harder for the clutch to slip.
Moving the clutch lever top left of the headstock operates the clutch and mechanically disengages drive into the head.




























I'd be interested in other owners views on the state of the friction surfaces as I've never seen these in "new" condition. I'm not down to the metal yet, but think this is a job that I'll need to tackle before long.


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## Sideways (9 Jan 2022)

Wrapping up, the L5 was the first significant piece of metalworking kit I'd ever overhauled. The simplicity of the old thing being a blessing and a fun lesson in how machines used to be built.
We had to empty half my garage to roll it in to the furthest corner where its small footprint allows it to tuck under the shelving without making everything impossible to reach.
Seriously wood and metalwork in a singe garage is pushing it a bit !









A few chips just to prove that it works, 





and a work in progress of the control box that I'll wire in eventually. This will give me an actual rpm readout directly off the spindle using a cheap RPM module and hall effect sensor as well as controlling the VFD with some sealed stainless "halo" switches to keep out the oil and coolant.





Thanks for reading. Please share your own overhauls. It's so useful to have some comparative pictures when you're working a machine for the first time.


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## Fergie 307 (9 Jan 2022)

Sideways said:


> I found a chap on ebay selling 3D printed ones for a variety of machines. I've fitted a set of his.
> 
> Clutch and brake:
> The L5 has a spring loaded clutch and brake concentric with the upper pulley driven by the motor V belts.
> ...


Unless yours is completely different to any I have seen before then unfortunately I think you are missing some bits. Do you know what the front of the pulley looks like If you remove the scored disc? I suspect you will find it has six holes around the inside face. These would hold the six clutch pins, which mate up with a fiction disc with six holes in it. Have you got a handbook for it? You can download one free as a pdf at vintagemachinery.org. If you look at the exploded diagram in the book yours is the older type clutch, the one that appears as the lower of the two sets of drawings of the two clutch options. The upper drawing is of the later high speed version. What you are looking at In your picture, with the two brass pins is actually the braking mechanism. Have a look at the drawings and compare with yours. I may have a spare disc, will have to have a rummage. Let me know when you've had a look, but if your pulley has the six holes then you are definitely missing the clutch plate and pins.


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## Fergie 307 (9 Jan 2022)

Looked in my manual and seems to confirm what I remembered. You should have two sets of discs either side of the pulley. The ones with the two brass pins should be behind the pulley, with another set in front, which you appear to be missing. Not really a massive problem, I never really use the clutch on Mine as I have the lever on the front controlling the vfd, in the same way as your button box will. Only ever use the brake if I need to hold the chuck still, say to do a keyway. The brake on my vfd brings everything to a stop plenty quick enough.


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## clogs (9 Jan 2022)

A great read.....and a jolly good job.....another one saved....
I have a heavy lathe and also a Bridgeport J headed mill.....
The lathe was to low for comfort so I built a heavy stand/chassis with adjustable feet....
I also did the same for the mill but needed a raised duck board for that....
reason for the frames was so that both machines could be moved with a pallet truck on my own.....
The room was tight in the shop...also shared with Wadkin wood machines....
so for the bigger jobs it was a game of Chess to get everything in the right place.....
Thanks for ur trouble to show us the work done....always an interesting read....
partiq the gear repair...that kinda job always worried me....


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## Sideways (9 Jan 2022)

Cheers Fergie !
I do have a pdf of the manual. I will study the diagrams based on what you advise.
Looking at the part that has the rollers of the taper roller bearing still in it, I had assumed the friction material on one side was for drive, the opposite side for brake. Feedback like this is incredibly useful. Appreciate it !


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## Fergie 307 (9 Jan 2022)

If you can get the drawing, and assuming that it's numbered the same as mine then the bits you appear to be missing are the two plates numbers 32 and 33, and the six pins number 34.


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## Fergie 307 (9 Jan 2022)

The later machines have a separate brake inside the headstock. Long time since I have seen an old one but as I recall the brake and clutch functions are both performed by the discs either side of the pulley, depending which way you work the lever, there is no brake inside the head. So the ones you have showing, with two pins, are supposed to be behind the pulley, or maybe the pulley itself is on the wrong way round. The recessed section in the centre of the pulley should be plain on one side, and have six holes in the other side. The side with the holes is the front. This is where the clutch pins go, the pins I suggested you should check for wear. You must have wondered what I was on about as you haven't got any ! You can only put it back together as you found it, looks like someone has messed with it before. Very possible the clutch pins broke or whatever so they just took that part out. Have a look at the cross section of the clutch under maintenance. Confusingly, in my book anyway, the drawing is actually of the later type with two friction plates in front of the pulley, and none behind. Yours is very similar but only has one plate in front. Also looking at this drawing you should still have a cross pin as shown to the left of the collar D, part 26 on the exploded view. I will have a rummage through my spares tomorrow and see if I have any of the stuff you are missing.


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## Sideways (9 Jan 2022)

Here are the diagrams that I think Fergie and I are both looking at.
The gear head of the L5 complete (shows both my 9" L5 and the later 11" L5A)





Zooming in on the clutch and brake components





It does look like I'm one disk short from the stack in my picture a couple of posts above.



With use of a lathe and a mill, it may well be possible to replicate the missing metalwork if I can get a better photo or some dimensions for the parts.

The correct friction material may well be the biggest challenge.

This will keep me busy for a few days  Fergie, thank you for pointing out the problem to me !


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## Fergie 307 (9 Jan 2022)

First thing will be to check If you are missing anything else. The main clutch shaft is hollow and has a slot cut through it. Inside is a rod which should have a hole in it aligned with the slot. The pin, number 26, has a spline cut in the centre portion of it and is driven into the hole in the inner rod, so it projects to either side of the main shaft. Have you got the pin? If you look at the part that fits under the spring that looks like a cowboy hat, this should have a threaded insert in its friction face. It's this part that the pin bears against, part D in the cross section. Some don't have this, so only a problem if you have a threaded hole but no insert. When you strip off the pulley, so you have a bare clutch shaft you should be able to see a collar round the base of the shaft. When you move the clutch lever to and fro this should move in and out, and the pin should move up and down the slot in the shaft. They way it works is that when you move the lever to the left the pin pushes against the cowboy hat, compressing the spring and so releasing the clutch disc which should be fitted in front of the pulley. Continuing to move the lever to the left causes the collar at the back to push the discs behind the pulley together, activating the brake. When you move the lever to the right the whole process is reversed, releasing the brake, and allowing the spring to push the front clutch plate into its mating disc to transmit the drive. Hope that makes sense.


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## Fergie 307 (9 Jan 2022)

Sideways said:


> Here are the diagrams that I think Fergie and I are both looking at.
> The gear head of the L5 complete (shows both my 9" L5 and the later 11" L5A)
> View attachment 126446
> 
> ...


So the plate 33 slides to and fro on six pins in the front face of the pulley, and is sandwiched between 32 and 35, both of which are keyed to the shaft. I don't know exactly what the friction material is, but it's metal. The original plates are steel with a disc of what looks like some sort of bronze bonded to either side. I will let you know when I have had a look through my bits and pieces, should be able to do it tomorrow. Always happens just when things seem to be going smoothly. On mine it was the Norton box, gave me all sorts of grief.


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## Fergie 307 (9 Jan 2022)

On the pulley the pin holes are normally blind, a daft idea to my mind, as it makes the pins pigs to remove. From the factory the holes are I think 1/4 On the early machines. On ones I have repaired I drill right through the pulley with a smaller diameter, say 4mm. This enables you to easily insert a drift to drive them out from behind if you ever need to change them in the future. It's also useful if any of the pins have broken off in the holes. They are hardened so not easy to drill out. Easy enough to drill through the base of one of the others you can get out and then index around to drill in behind the broken one and drive it out.


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## Sideways (9 Jan 2022)

I have scratched my head at the drawing for a while and crawled the internet looking for photos. There's a great pictorial elsewhere of an L5A rebuild with detailed clutch photos but that is the "other" part of our exploded diagram above.
Just one phot in internet land shows an L5 and a string of parts similar to mine. I look to be minus a complete free floating disc and one or more discs of friction material associated. I guess that it simply wore out - maybe first because of inadequate maintenance - and being obsolete, the owner at that time simply removed the layer and turned a triple decker sandwich into a double decker ! I'm also guessing without studying the mechanism but I imagine that the clutch side of the sandwich was the multiple layer one to cope with the turning forces, while the brake side was a single friction layer adequate for slowing down the spindle once power was uncoupled.

The friction pads that I have left are black, almost like a rubber material. Very definitely not a hard asbestos like pad, Not even if it were contaminated by oil / grease thrown off from the roller bearing in the middle of the pulley.

I've noticed the two brass pins on one inside of my triple V pulley, now ground flush and yes, the pins are in blind holes so the reverse side of the pulley is a smooth face for another friction disc to bear on.. I was curious about that. My guess is that those pins were there because a layer of friction material was bonded to the inside of the pulley on that side only. The brass pins stick up into holes in the friction pad to transfer torque to them. Gluing the pad on wouldn't have been strong enough to resist the shear forces. This is repeated elsewhere. The pairs of pins don't go all the way through the friction material but if the pad wears down too far before being replaced, the brass pins would wear out rather than scoring the iron of the mating disc.

The old pad and any remnant of the pins was probably machined out of the pulley so that the outermost friction disc could then bear on it after the floating disc was removed from between.
I have none of the smaller springs or washers that were involved with (probably releasing) the floating disc of the clutch.

When you do have time to look through your box of bits, I'll be grateful to see what if anything you find. I won't be able to strip my clutch again for a day or two but I'll post the pictures of the spindle, anything in it and the details of the key etc when I do.

Although it's disappointing to find part of your machine has been excised, it's an interesting detective job to figure out how and why, and to discover how it should be. That's part of what makes tinkering good fun


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## Tony Works Wood (10 Jan 2022)

Sideways said:


> Excellent Tony. Thanks
> Yes, I believe mine is an L5 mk3 and yours is slightly different though v similar.
> Hope you are enjoying the 140. The L5 is a proper lathe with a useful capacity but it's strange to have the same 1.5" 6tpi threaded spindle on a metal lathe as they used on the graduate wood lathe !
> Your newer 140 is nice step up the range !


I have some videos using the Harrison 140 on YT under the channel name EYUP TONY. They probably standardised the Graduate's spindle nose for quickness in productions as the screw cutting machines would be already set up for the L5's. I have recently acquired a Harrison Jubilee wood lathe to overhaul not as in depth as your L5 though lol..


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## Fergie 307 (10 Jan 2022)

If you look at the thread Harrison L5A clutch troubles on the mig welding forum there is a photo of your clutch setup. He has the notched friction plate and drive plate the wrong way round in the picture, but the parts are the same. As standard the 5A didn't come with the high speed clutch, you had to pay extra for it. So early 5A machines have the same clutch as the 5. They standardised the high speed shaft later, at the same time as the hardened bed, about 1956/7. This design was then carried forward on all later machines including the 140. There are two types of friction plate the one on the forum pictures is the earlier type with notches around the outside which engaged with the pulley pins, these are made of a hard plastic or resin material similar to bakelite. The later type have a larger steel disc with holes rather than notches, and the friction surface is made of a metal, similar in appearance to bronze. One problem with Harrison is there is not necessarily any consistency. Partly because they were happy to build machines to a customers requirements, and partly because they have often been messed about with. The upshot is you can never predict exactly what set up you will find on any given machine. What the pulley looks like and how the driven pins are configured will be the key to knowing how it was set up originally.


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## Fergie 307 (10 Jan 2022)

I know Chris Redrup on the io group has the same clutch on his, or did have. He's done a lot of mods to his head so may have changed it. Might be worth putting a message on the group.I will have a look to see what I have later today.


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## clogs (10 Jan 2022)

I was gonna say a lot of those kinda clutches used sintered bronze.....
this material is also used on older clutches used on fork lifts n yard tractors where 
the norm asbestos type cluch friction material would fall aprt really quickly.....
My thinking is this lathe wont be used for production purposes an asbestos disc would be ok....
that unless u can find an original....
also there are plenty of firms outthere that will make up friction disc's tour design patern....
I had some done for the front forks of a 20-30 American m/cycle..think they were about a £5'ver each....esp as none are being made anymore...


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## Fergie 307 (10 Jan 2022)

Had a rummage through the bits I have, unfortunately they are all of the later type, so no use to you. Probably worth putting out a cry for help on the Harrison lathe group. I know Chris had the same clutch on his, and there will be others who have them. If you are really lucky someone may have the parts you need. Failing that I dare say someone would be prepared to take measurements and photos for you. Once you have the dimensions then as Clogs says there are plenty of firms that can run you up a suitable disc, or supply the material. The other bits should be easy enough to make once you have the measurements.


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## Sideways (10 Jan 2022)

I have appealed to the elders 
Fingers crossed !

Thanks for the other reference. I'd spotted that one photo of the parts threaded on a stick. V. glad to have your comments on how to interpret it though.


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## Fergie 307 (10 Jan 2022)

Good luck. And congratulations on your work so far, nice to see the old girl in safe hands. I am sure it will reward the hard work and care you have put into it with many more years of good service.


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## Fastdruid (11 Jan 2022)

Fergie 307 said:


> Unless yours is completely different to any I have seen before then unfortunately I think you are missing some bits. Do you know what the front of the pulley looks like If you remove the scored disc? I suspect you will find it has six holes around the inside face. These would hold the six clutch pins, which mate up with a fiction disc with six holes in it. Have you got a handbook for it? You can download one free as a pdf at vintagemachinery.org. If you look at the exploded diagram in the book yours is the older type clutch, the one that appears as the lower of the two sets of drawings of the two clutch options. The upper drawing is of the later high speed version. What you are looking at In your picture, with the two brass pins is actually the braking mechanism. Have a look at the drawings and compare with yours. I may have a spare disc, will have to have a rummage. Let me know when you've had a look, but if your pulley has the six holes then you are definitely missing the clutch plate and pins.



Sorry but it _is_ completely different and this is wrong. You are describing the much later clutch. The manual on vintagemachinery.org is from 1965 and the clutch changed a *lot* between '49 and '65! There is also no brake fitted to this. 



Sideways said:


> Here are the diagrams that I think Fergie and I are both looking at.
> The gear head of the L5 complete (shows both my 9" L5 and the later 11" L5A)
> View attachment 126446
> 
> ...



The diagram is out of the 1965 Manual which would be the "Mk4". Unfortunately Harrison in their infinite wisdom operated more on a policy of continuous improvement so the various "Mk's" are given by people to try and differentiate them rather than being official. This means that there was significant overlap between the different "Mk's" and having the correct manual for your year of Lathe is vitally important. The later manual is still useful as most bits are still really close and shared but from the look of your pictures the clutch arrangement appears closer to the ~1944-~1949 "Mk2" (ignore what lathes.co.uk says on the Mk2 being from 1946, mine is a "Mk2" and dated 1944 and I have a 1945-47 manual that is clearly for a Mk2). 

I would in the first instance ask Colchester/600 Group spares (Colchester Machine Tool Solutions spares enquiry - Colchester Machine Tool Solutions ) if they have the correct manual for your machine (give them the serial from the end of the bed).

So on the assumption that it should look more like the (closer in age) Mk2, your pulley should not look like this. 







But instead should look more like this. Note those two brass pins standing proud and the lack of wear to the pulley vs yours. 






The part you appear to be missing is this, a DC.1 "Halo" Disc of which the early L5 had 3 vs the 1 in the later L5 shown in the 1965 manual 






This is identical to the other two in the assembly (two on the left, one on the right) and it then fits like so. Locating in the two pins on the pulley to prevent it from turning. 






The later L5 changed this to instead be a single floating DC.4 "Halo" disc that had 6 drive pins onto the pulley, a "Clutch Plate, centre" on the right of it and the "Clutch plate, LH" to the left. The right hand side of the pulley however was relatively unchanged with the same DC.1 "halo" disc.

It is entirely possible as that DC.1 "halo" disc was used right up until the 60's that Colchester/600 Group may have spares still. Dread to think how much but might be worth asking.


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## Fergie 307 (11 Jan 2022)

Agree entirely. That's why I said the crucial thing was to look at the pulley and see what it looked like, if the six drive holes were there for example. My initial thoughts looking at it were that what we were looking at was The brake disc from the later smooth shaft type, which was why I asked what was underneath it. If this in fact the front face of the pulley itself then as you say it's the really old one, which I wasn't aware was even used that late. Only ever seen one of them, on a much older machine which was why I have thought it was the one I described. You learn something new every day.
Sideways, please accept my apologies if I have inadvertently led you in the wrong direction, but at least you have hopefully now got the full answer.


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## Sideways (11 Jan 2022)

All the advice here has been useful - appreciate it gents. Fastdruid - very good of you to sign up here and share your photos. Excellent !
Now I'm better educated, I've figured this is a 1950 year of manufacture not a 1949. Still older than me though


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## Fergie 307 (11 Jan 2022)

That's the beauty of the forum, and the Harrison group. There will always be someone who knows the answer. In the case of your clutch I was mistaken. I hadn't realised that type was still in use so late, but Fastdruid has put me straight, so I have learned something I didn't know, and you have the answer to your problem. Good luck with the repair, will look forward to seeing the end result.


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## Fastdruid (13 Jan 2022)

Excuse the crudity. Spring isn't shown but that's pretty obvious where it goes.


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## deema (13 Jan 2022)

That’s super brilliant, Sideways is tracking down a suitable source of friction material. Would it be possible m, and I know this is a big ask to get dimensions of the friction plates?


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## Fastdruid (13 Jan 2022)

Friction plates are 4" OD, 2" ID and 3/16" thick. Holes appear to be 1/4" at 3-3/8" PCD.


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## Fastdruid (13 Jan 2022)

Sideways said:


> The standard L5 came fitted with a 6 pole motor (just under 1000 rpm) that gave a speed range from 21 to 480 rpm.
> It was also available with a 4 pole motor and a twin speed (2 or 4 pole motor). Depending on the motor that gave top speeds up to 720 or 1440 rpm. very low by the standards of today where lathes may hit 3000 rpm or more to turn smaller parts with replaceable insert tooling.
> 
> With a 2.2kW 4 pole motor I have plenty of power available and the variable speed option. I've configured the VFD to spin the motor faster than it's design 1400 rpm. 4 pole motors are physically almost identical to 2 pole, so there will be no mechanical reason that it can't take 2800 rpm if I wanted, but when the lathe was sold with a 2800 rpm motor, it was also given a second bearing on the tail of the shaft. I won't try to go that fast. My setup will allow maximum power upto 720 rpm but thanks to the VFD can be increased to 1000 rpm at reduced torque for light cuts.
> ...



FWIW my L5 was originally also a 480rpm version. As there are no significant changes until they increased speed to 2000rpm (and even then only in the pulley) I felt confident enough to run it faster. I replaced the motor on mine with a similar 1425rpm 2.2Kw 4 pole (VFD rated 5Hz to 90Hz which would spin it from 142rpm to about 2500rpm) and kept it as roughly a 2:1 ratio so that with the over and underspeed using the VFD I had a speed range of 4RPM to 1296RPM (with roughly 720rpm at 50Hz).

After running this for a number of years I replaced the motor pulley with a 140mm (the wonders of taperlock bushes means it takes about 20mins).

Top speed now is now a rather terrifying 2400rpm (I've actually never dared do that) and at 50Hz it's a very reasonable 1440rpm or so (bit cold here, it'll gain a few rpm as it warms up).






At the same time I put a variable resistor onto the VFD so I can vary the speed with ease rather than messing with the VFD controls.

For the terror of a >75 year old lathe running at 3x its design speed, there is a short video here: 1940's Harrison L5 at 1430rpm


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## Sideways (13 Jan 2022)

It's encouraging to know that these old things can go that fast and not shake apart or overheat 
That extra speed can be very valuable when you are using insert tooling and trying to get the surface feet / minute high enough.
Like minds on the choice of motor and VFD config .... 

I appreciate the drawings and dimension details. I'll strip my own clutch and measure it for comparison but after that it's time to start ordering material.


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## Fergie 307 (14 Jan 2022)

On mine, a 5a with the high speed shaft, I reconfigured the original coolant switch to give two positions. These control two pre set frequencies on the vfd. The original 1.5hp 1400 rpm motor has been changed for a 3hp 2800rpm. So I tweaked the lower frequency to give the same top speed as the original plate on top of the machine. The higher setting runs the motor at full speed, giving a top spindle speed of 1500 rpm. I then used a laser tacho to get the hi range speeds in each gear. I got a local print shop to make up a new speed plate, using an old two range plate as a pattern, so I now have the plate showing the correct speeds in each gear and speed range, imitating the set up on the machines that originality a two speed motor. Obviously the new plate is printed rather than the cast original but looks ok. 
And Harrison's are well known for being quite noisy. The headstock gears are all hardened so they ring, especially when it's at full speed in the high range. Mine isn't too bad but some do make quite a howling noise!
Excuse the horrible modern stop switch. I have the original plate with green an red buttons, but the associated switches were well past their best. It's on my to do list, in the meantime this was one I had lying around.


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## Fergie 307 (14 Jan 2022)

I should add they printed a number of the plates, so I still have a few if anyone is interested just pm me your details and I can post you one.


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## Fastdruid (14 Jan 2022)

Fergie 307 said:


> I got a local print shop to make up a new speed plate, using an old two range plate as a pattern, so I now have the plate showing the correct speeds in each gear and speed range, imitating the set up on the machines that originality a two speed motor. Obviously the new plate is printed rather than the cast original but looks ok.



I like that. Unfortunately not much use with the infinitely variable control that a VR gives. I left the original alone and stuck this above the lathe. It gives an idea of rough speeds at a given frequency and then can use the tacho to fine tune things (note that although the motor is rated 5-90Hz I'm sticking to +/- 33% from 50Hz).






I've attached a version of this I recreated (I lost the file from the one I initially created) if it is of interest in working out the relative speeds. 



Fergie 307 said:


> And Harrison's are well known for being quite noisy. The headstock gears are all hardened so they ring, especially when it's at full speed in the high range. Mine isn't too bad but some do make quite a howling noise!



I don't actually think mine is very noisy at all. I mean it's not quiet but from reading about them I thought it would be horrific. Most of the noise is from the motor itself. 



Fergie 307 said:


> Excuse the horrible modern stop switch. I have the original plate with green an red buttons, but the associated switches were well past their best. It's on my to do list, in the meantime this was one I had lying around.



Better than mine there. Mine is horribly modern as the original had a massive great contactor on the front (unlike the newer ones which have a nice control panel). So I cut a hole in the cabinet akin to the newer ones and fitted a panel with the controls etc on...but modern ones.


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## Sideways (14 Jan 2022)

PM incoming Fergie,
I like your new speed plate and would be pleased to adopt that.
For me, I'll stick to 1500 as my top speed until and unless I have the need to go faster.
Thanks for the offer to share


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## Fergie 307 (14 Jan 2022)

I have got that, will get it off to you over the weekend. I have limited mine to 1500 purely out of respect for the old girl. She is slightly older than me, and I know I certainly cant run as fast as I used to !
Many people of course choose to vary speed with the vfd, I suppose I am a bit old fashioned and still prefer to use the gears. You can of course combine the two to fine tune, whatever suits best for your particular needs.


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## Fergie 307 (14 Jan 2022)

Fastdruid said:


> I like that. Unfortunately not much use with the infinitely variable control that a VR gives. I left the original alone and stuck this above the lathe. It gives an idea of rough speeds at a given frequency and then can use the tacho to fine tune things (note that although the motor is rated 5-90Hz I'm sticking to +/- 33% from 50Hz).
> 
> 
> 
> ...


I was a little concerned at halving the frequency for the lower range, as I know some motors aren't keen and can overheat. This one is fairly modern and runs quite happily at half speed. I am old fashioned enough to prefer using the gears for changing speeds, but can certainly see the attraction of your set up. I am with you on some of the modern ones that look more like a jukebox than a machine tool.


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## Fastdruid (14 Jan 2022)

Fergie 307 said:


> I was a little concerned at halving the frequency for the lower range, as I know some motors aren't keen and can overheat. This one is fairly modern and runs quite happily at half speed. I am old fashioned enough to prefer using the gears for changing speeds, but can certainly see the attraction of your set up. I am with you on some of the modern ones that look more like a jukebox than a machine tool.



Mine is inverter rated down to 5Hz but still, I prefer to keep it 33-66Hz. If I was to run it any less I'd want an additional fan on it.


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## sploo (14 Jan 2022)

Always worth checking the motor specs if you can find them. The one that came with my Colchester Chipmaster turned out to be rated for some crazy range. I can't remember the exact numbers but from 50Hz nominal it can handle 100Hz down to something daft like 5Hz. Power drops off significantly at lower rpm, but the motor can do it.


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## Fergie 307 (15 Jan 2022)

Sideways said:


> PM incoming Fergie,
> I like your new speed plate and would be pleased to adopt that.
> For me, I'll stick to 1500 as my top speed until and unless I have the need to go faster.
> Thanks for the offer to share


In the post to you this morning. Good idea to put a smear of Hylomar or similar on the threads of the screws that hold the plate on. Otherwise over time oil seeps past them and puddles in the top under the plate. My perspex cover was pretty much opaque, I made a new one out of some clear acrylic left over from windows in a wendy house I made for my daughter, been sat behind my bench for best part of twenty years in the basis that it might come in handy one day!


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## Sideways (15 Jan 2022)

Excellent advice  I'll take it.
Elsewhere, I've not started on gaskets yet. Mine leaks in fine style from around the headstock top cover, also slowly through the bolts down into the bed. Not too much, but enough to supply my oily rag maintenance regime. I believe that BMW engines for example are actually deigned to consume oil, so I don't see this as a problem for now as long as I keep an eye on the levels.


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## Fergie 307 (15 Jan 2022)

Sideways said:


> Excellent advice  I'll take it.
> Elsewhere, I've not started on gaskets yet. Mine leaks in fine style from around the headstock top cover, also slowly through the bolts down into the bed. Not too much, but enough to supply my oily rag maintenance regime. I believe that BMW engines for example are actually deigned to consume oil, so I don't see this as a problem for now as long as I keep an eye on the levels.


The top cover I find is best done by putting a thin bead of automotive type silicon round the cover, about a millimetre or so wide. Hate the stuff normally, but for this it is very good. Let it go off a little till it's tacky, then put it on and just nip the bolts up not much more than finger tight. You need to be careful to keep it close to the outer edge at the front so you dont risk any getting into the oil trough round the front of the casing. If you rub a little Vaseline over the mating faces on the headstock before you put it on it will still seal but the silicone will stick to the cover, not the casing. You can then take it off maybe a couple of times and replace it before you have to redo the sealant.
For the bolts, a little Hylomar or Wellseal under the washers should do the trick. Just do them one at a time to avoid it moving. To clean all the oil out of the head I find one of the oil full guns for filling gearboxes is very handy. Basically a big syringe with a body like a grease gun, and a plastic hose. Enables you to easily suck up the last of the oil from the bottom of the case, and any sludge that collects there.
Can't remember now if you had the gap in yours. If not then you might want to make a plug for the hole in the bed under it. On mine so much crud and oil had accumulated in the hollow section under there that it had started to bleed out around the joint with the chip tray. Used a piece of plastic pipe on my shed vac to clean it all out. Probably got a couple of mug fulls out of there eventually. Now if I take the gap out I have a rubber plug to pop in.
A tip my dad gave me for these is that the strip at the back of the saddle is a potential spot for wear, and has no specific lube points, it relies on oil you pump into the way oilers working it's way down. His tip was that as well as giving all the oiling points a couple of strokes from time to time during a session, when you have finished for the day give the rear way oilers in particular a good feed, that oil then has plenty of time to work down into the rear strip before you use the machine next time.
Oh and for lubricating the change gears I find the spray motorcycle chain lube is good. Tends to stay put on the gears rather than all over the inside of the covers. 
Have fun.


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## Fergie 307 (15 Jan 2022)

Lastly while I remember. If your white knobs on the machine are in a poor state, which they often are, I found it quite difficult to get hold of white ones of a decent quality from the normal places. The knobs on mine I stumbled across on e bay. They are actually sold for joysticks on gaming consoles. They do all sorts of sizes and colours including white. They come with an M6 brass insert. They knobs are a thermo plastic of some kind, so I found the easiest way to remove the insert was to use a piece of M6 threaded rod. Just heat it up a bit then screw it into the insert. Once the heat spreads to the insert it softens the plastic around it and you can just pull them out. They are then easy to drill and tap to the correct size Not sure exactly what they are made of but good quality finish with no central ridge. I was a bit concerned they might discolour, but they seem impervious to oil and coolant and still look like new after more than two years of regular use.


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## Sideways (17 Jan 2022)

Making some progress on the clutch upgrade. I've identified a modern material that may make a good replacement disc and an excellent supplier who is educating me about the materials and processes. A number of folk from the Harrison lathe group have all contributed measurements and from that I'm having some friction material made and precisely ground to thickness as this seems to be important to the correct operation of the clutch. More to come on that story.

Meanwhile, I'll have to strip my own clutch for machining to reinstate the driving pins that are needed for the 3 plate design.
First job - get a pin hook spanner as the compression nut on the clutch shaft is distinctly harder to undo than it is to tighten up  
Here's the end of the lathe with the cover off:










And while I'm at it, the clutch lever which I had not previously taken apart. 
There's a boss which turns L and R, the lever on a sizeable straight pin. Small grubscrew from above locks the pin in place. A spring loaded plunger holds the ball end of the lever down. Lifting the lever raises a square tooth from a notch and allows the clutch lever to move R which in turn causes the clutch to grip.


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## Fastdruid (18 Jan 2022)

FWIW I've found just using a suitably sized pair of drill bits in the holes for the clutch nut gave sufficient leverage to undo it. Certainly a pin hook spanner would be useful but I've never found I actually _needed_ one.


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## Sideways (18 Jan 2022)

Fastdruid said:


> FWIW I've found just using a suitably sized pair of drill bits in the holes for the clutch nut gave sufficient leverage to undo it. Certainly a pin hook spanner would be useful but I've never found I actually _needed_ one.


My nut has just one pin hole in the outer edge, not the face. It accepts a 4.5mm drill bit, maybe a 4.8mm but 5.0 is too big.
This worked great for tightening it by hand against the spring but strangely it is harder to loosen than to tighten. I snapped the 4.5mm drill and nearly skewered myself. I'll be more careful next time !


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## Fastdruid (18 Jan 2022)

Sideways said:


> My nut has just one pin hole in the outer edge, not the face. It accepts a 4.5mm drill bit, maybe a 4.8mm but 5.0 is too big.
> This worked great for tightening it by hand against the spring but strangely it is harder to loosen than to tighten. I snapped the 4.5mm drill and nearly skewered myself. I'll be more careful next time !



Mine has two but same design, holes on the outside edge. I wonder if it's because yours has been tightened up more than it should be because of the missing plate. Yours looks almost coil bound while mine is barely tightened. FWIW there isn't a procedure in the manual beyond tightening it until it doesn't slip. I tightened mine by hand until it didn't slip turning by hand while holding the chuck with a bar then 1/2 turn more. Check it released properly and job done. I figured in general it's actually better to slip at the extremes as it could save things getting nasty if you have a crash or something digs in etc.


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## Sideways (18 Jan 2022)

Mine certainly slips on excessively heavy cuts - that or it's the belts slipping. I agree it's a good thing to prevent damage.
You can see how the inner steel plate of my clutch sits lower the face of the pulley vs yours standing proud. The 5mm of the missing 3rd plate will account for that.
Having no friction <=> friction surfaces in contact, I'd expect mine to slip more easily than it should.

Anyway I've been able to borrow a hook + pin spanner from a friend with a later model 11" L5A so I hope it will come off tomorrow


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## Fergie 307 (19 Jan 2022)

Once you have it all sorted and clean you should find you can adjust it without tools. A work glove with a rubber palm gives enough grip. With the plates in good condition it shouldn't need to be very tight. The old ones are easier as you only have the clutch. Getting the brake/ clutch balance right on the later ones often involves a lot of fiddling about.


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## Fergie 307 (19 Jan 2022)

Judging from the pictures it looks to have cleaned up really well, I can imagine a fair bit of work went into getting it looking like that. Out of interest is your speed selection lever a similar design to the clutch lever, where you have to pull it out before moving it, or the type with no detent.


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## Sideways (19 Jan 2022)

The high low range lever on the front is like my clutch lever. Theres a detent so you pull and swing it from one side to the other. That's one of the features that lathes.co.uk mention as a difference between a mk2 and mk3 version of the L5.
I'm learning that these mk2, mk3 designations are kind of artificial tags that weren't used by Harrison and there's more gradual improvement than I realised.


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## Sideways (19 Jan 2022)

On the subject of cleaning. One of the most useful accessories for a metalworking lathe is a quick change toolpost. With this, tools are clamped into blocks, height adjusted to put the tip on the centre line and then locked off. A part turn of one bolt allows the block to be removed and a different one dropped into place. This is a great time saver as most turning requires a few different tools to be swapped in an out.

The block or QCTP drops on over the post on the top slide where it can be rotated to bring different tools to bear or angled if required. 






A sleeve is often needed to match the post of your lathe to whatever quick chnage or other toolholder you choose.

My L5 came with a popular style of QCTP. A copy of the UK designed Dickson T2, but no holders to fit. It was very gummed up and took most of 5 hours to clean.
There is a lesson in this. The Dickson type block can be disassembled for cleaning in literally seconds with no tools. Simply push in the locking plungers against their springs and the locking cam pulls straight out. If you neglect the cleaning discipline, swarf builds up behind the locking plungers (or top hats) making it near impossible to push them in far enough to pull out the cam pin. Swarf bound up in dried oil and lousy maintenance is why it took 5 hours to clean something that should have taken 2 minutes.














Although a copy of the Dickson design, my block is labelled "Rapid Benrath"
There were two Italian companies, maybe three, who made quality copies of the Dickson back in the day under the name of Rapid, or similar. You can still buy Rapid toolposts and holders from Italy and I believe the quality is good.

Rapid Benrath however gives me almost nothing. There was a UK importer with the Benrath name back in the 1950's and Benrath is a place in Germany where machine tooling was made. There's likely a connection.
My toolpost is very nice quality. Hardened, ground. Just 2" tall, compared to a Dickson T2 which I think is 2.5" but otherwise dimensions are as close as I can tell and Dickson toolholders drop straight in.

Disckson T2 is a middling size, strictly too tall for my lathe which will only swing 9" work. The upshot is that I cannot use any larger than 16mm shank tools and still get the point low enough to line up with the centreline of the spindle.




A smaller T1 toolpost would be better suited to the L5. I borrowed a T1 Tall to see how it sat on the lathe. Perfectly good, but even with a T1, the toolholders hang over the end of the top slide.





It looked such a fragile little thing compared to the T2 that I decided to stick with the excellent Rapid Benrath block even though it's farr too big and several weeks on, I was able to buy some genuine Dickson toolholders to fit it.

Original toolholders are a bit like investing. They cost a mint but tend not to lose value. Good Dickson ones are much more expensive than Chinese or Indian copies. I stumbled onto a set of 5 toolholders on ebay, never unpacked since they were made in the 1970's. They were made by Dickson, boxed up and sent to Harrison who sold them on, probably with a new lathe. They still had the anti rust wax on them. Opening the box which looks like it dates from the 50's never mind 70's , I could imagine what an archaeologist feels like  

I measured the blocks for reference. Factory new vintage original are pretty scarce, so I photographed everything with zero wear and tear





---


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## Fergie 307 (20 Jan 2022)

Don't think you will have any issues with the overhang on your toolpost, and the holders were quite a find. I have an oversized piston type on mine, purely because the machine came with loads of 7/8 tooling which is too big for the holders on the "correct" size post. It does overhang, but so solid I've never had any problem with it.


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## Fastdruid (20 Jan 2022)

S2/T2 (designation depends on brand) are far too big for the L5, nice fit for the L5A/L6 and 140 but you want an S1/T1 for the L5. Otherwise as you've found you just can't get the centre height low enough. The S1/T1 are designed with 19mm x13mm tooling which is exactly the same as the S2/T2 anyway. 






Dickson Quick-set Toolholders


How the lathe works. Names of lathe parts. Screwcutting. Generating changewheel charts. countershafts. backgears. tumble reverse. Stuck chucks. Quick-change toolposts. Fitting a chuck Spindle nose fittings, backplates, Oiling



www.lathes.co.uk





Overhang isn't really an issue, you're going to have that on pretty much any QCTP.


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## Sideways (22 Jan 2022)

With a proper pin spanner my clutch disassembled easily.

Here are the parts





The outer one of the two "halo" or DC1 friction discs gave me measurements (4" 101.6mm outside, 2" 50.8mm inside) and at 3.7mm thick is clearly worn compared to other owners who have been measuring theirs at 3/16" appx 4.8mm















Here's the side of the drive pulley and the 1/4" brass pegs that should drive another friction disc but have been machined down so the outer friction disc can bear directly on the metal.
This is a bodge because one of the original three friction discs wore out and they couldn't replace it.






The cross pin in the shaft moves left<>right with the operation of the clutch lever to push the outer clutch pad and it's backing plate away from the drive pulley.

Measuring the cross pin in the engaged and disengaged positions, it moves only 3.4 mm
















A small steel washer with clear wear marks acts as a shim to position the outer clutch plate at an appropriate position when disengaged. It slips onto the shaft, against the cross pin and the outer clutch plate + backing disc slide upto it and are pressed there by the big spring.




In my case, this shim washer is 1.67 mm thick, bearing in mind I'm missing an entire 4.8mm thick clutch plate !





When the clutch lever is moved to drive, there is 3.4mm of movement in the cross pin and the clutch plates have to achieve full pressure contact within that distance.

The drive pulley has a taper roller bearing so this this is easy to pull off once the belts are removed. The pulley will go on the mill and the brass plugs be drilled out and replaced with new ones that stand about 3mm proud of the surface.

I'll then make some new halo discs once my pad material arrives and will have to re shim the assembly so that the renovated 3 pad clutch is able to open and close correctly.


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## Sideways (28 Jan 2022)

First a thank you to Fergie. He kindly sent me a new speed chart / gear selector label for the L5 that reflects the increased speeds available with a non original motor. V smart and I'll proudly add it to mine once I have some fresh perspex and a backing plate to do it justice 

Next comes a big step on the renovation. My clutch material landed today. Applications of this modern friction material do include machine tool clutches, and it was precision ground to thickness for me based on feedback from other L5 lathe owners.

This is what it looks like ....





There is a strong stink of phenolic which is a good thing as I'm sure that's also a major component of the original halo discs.
It will take a few days to fit it in but I'm really interested to make up the discs and associated parts to try it out.


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## Sideways (5 Mar 2022)

Long overdue but machine time had to borrowed and other jobs get in the way.
Template made up for the inside and outside diameters and the holes for the driving pegs











Friction material has been routed into plates, Horrid job !





Brass pins turned up and fitted,
The original pins were 1/4" diameter and a slightly loose fit. I made the replacements v slightly bigger and chose a length to give me 3.5mm proud to drive the disc which is 5.5mm thick.














Of course once you start to drive the pegs in, you find that the original holes are tapered and uneven, so precise measurements end up being tweaked in situ with the dremel !




This is the inside. I decided to leave the original phenolic halo disc here as
a) it isn't too worn
b) my new clutch plates are an unknown, so until I know more I'll avoid the risk that they might abrade the cast iron of the pulley more than the original plates.

The new discs fit nicely on the outboard side









The L5 now looks more like it should.





Since the two new outboard clutch plates are much thicker than the single worn original disc, the washer that sits on the cross pin is much too small. I've reassembled without, meaning the clutch lever doesn't work, but I can start and stop the lathe motor so the lathe will work and I can use it to turn up a replacement spacer washer which will be about 8mm thick.


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## Sideways (5 Mar 2022)

And like everyone else, I'm putting an rpm sensor directly on the spindle


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## Fergie 307 (6 Mar 2022)

That's looking better! What was the friction material you went with in the end?


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## clivehearsey (28 Apr 2022)

What a brilliant thread, I have a 140 with a rattling clutch when idling, any ideas.


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## Fastdruid (28 Apr 2022)

clivehearsey said:


> What a brilliant thread, I have a 140 with a rattling clutch when idling, any ideas.



Different design to the 140 clutch. Probably the pins have worn and the matching holes in the plates are oval.


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## Fergie 307 (29 Apr 2022)

Fastdruid said:


> Different design to the 140 clutch. Probably the pins have worn and the matching holes in the plates are oval.


If you have the type with six pins its common for the plates to wear notches in the pins. This causes the rattling and so makes the operation of yhe clutch sticky. If you are lucky then you can take the holes in the plates out slightly oversize to get them round, and fit suitable oversize pins. Not a particularly difficult job.


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## sawtooth-9 (30 May 2022)

So many people put so much effort and time into restoring machines which would be best left.
Harrison and Colchester ( and a few others ) are worth every hour of work.
I had an L5 but it ran a little slow for me. I fully restored it about 10 years ago.
Now I have a Colchester Student Square Head - which I also restored - both have advantages over the other.
Congratulations, you have done a fine job.


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## Keith 66 (6 Jun 2022)

I have a late Harrison 140 (metric) came out of the college where i worked for a while. Unlike most it still has its original manual & factory test chart plus a large amount of tooling. Lovely lathe to use & still as accurate as the day it was made.
Re toolposts my Harrison has one of the rotating indexing toolposts mounted, I have not seen another one so fitted so its may have been an optional extra. A swift back & forth movement of the top handle spins the toolpost 90degrees & locks it down again. So you can set it up for a job as a 4 tool capstan & is really quick to use. Mine was a box of bits when i got it as it had broken, fixing it & setting it up was a royal pain!


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## Sideways (7 Jun 2022)

That sounds like an excellent toolpost. I have used one like that sometime back in my youth so I recognise your description.
I very much like the excellent Parat (Germany) quick change system that 600 group still offer as an option on their lathes. That has an integral locking lever (quite long) on top of the block with detents at 90 degrees but not the super fast auto indexing just from using the locking lever.


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## sawtooth-9 (10 Jun 2022)

Still torn between my Harrison L5 and the Colchester Student - square head.
I couldn't keep both even though I fully restored the Harrison. It ran a little slow for some of the work I wanted to do - but it was a beautiful machine.
Having had a Colchester Bantam, and now a Student 1800 - I am still " torn"
It is so great that some very special people appreciate Harrison engineering and are helping to preserve their engineering excellence.


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## sawtooth-9 (10 Jul 2022)

This is a great post, and really stands for what this site is supposed to promote.
Sideways - you should stand proud of, not only your achievement, and skill - but you choice a beautiful piece of engineering to restore.


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## Sideways (10 Jul 2022)

And like an old car, there is always something new to work on  
I can see me adding to this thread time and again as years go by !

There is no doubt that the Colchester Students are a far more sophisticated lathe with the benefit of hardened ways and much more, but I have a friend who managed to buy an almost unused Harrison 11" and in that nearly new condition they are a smooth, quiet and quite powerful small lathe.


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## Tony Works Wood (29 Jul 2022)

Sideways said:


> And like an old car, there is always something new to work on
> I can see me adding to this thread time and again as years go by !
> 
> There is no doubt that the Colchester Students are a far more sophisticated lathe with the benefit of hardened ways and much more, but I have a friend who managed to buy an almost unused Harrison 11" and in that nearly new condition they are a smooth, quiet and quite powerful small lathe.


I've never run a Student lathe. I could have bought many and the newer M series Harrison's as well but I love the clutch on the older Harrison's. Being able to sneak up close to the chuck jaws without pre judging when to disengage the feed, not being frightened of overrunning and colliding with the chuck jaws. My opinion only but I love the clutch it's like driving a car in stop start busy traffic. Check out some of my work on YT EYUP TONY I'm only an amateur but this feature is really beneficial when learning how to run a metalwork engineering lathe.


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## giorgio (23 Aug 2022)

compliment for good work! I am restoring my grandfather's old l5 lathe. unfortunately the charts for changing the pitch of the metric and whitworth threads have been canceled. could someone send me an image or a manual page where I can see the different combinations of gears? thank you


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## Sideways (24 Aug 2022)

My metric chart is worn out too but it is in the manual which can be found online and downloaded FOC.

Here's a scan of the imperial and Whitworth charts.





It isn't difficult to make a spreadsheet that shows all of the change wheel combinations and the feeds and threads that they make.
There are many more ways of combining change wheels than in these standard tables.


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## mattygp86 (14 Nov 2022)

Sideways said:


> Long overdue but machine time had to borrowed and other jobs get in the way.
> Template made up for the inside and outside diameters and the holes for the driving pegs
> 
> View attachment 130954
> ...


Where did you get the friction material from?


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## Sideways (14 Nov 2022)

It was custom pressed and ground with a minimum sheet size sufficient to do a number of lathes.
I may be able to help if you need enough for one.


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## clogs (15 Nov 2022)

Sideways
has ur student a clutch or a brake....I was told u can't have both....
Mine has the brake, which was faulty....played with it for awhile but I just made it a solid drive.....
it now has a clutch of sorts....
it's just the motor now sits on a swivel plate and is raised slightly by an old ride on mower deck lift lever.....
not the prettiest thing but it was done quickly with what was laying around.....
plus it has to work for it's keep.....
gotta say it works well and the belts have never come off.....lol...
will also modify the counter balance for the splash guard in the future....that paint tin has a load of 20mm nuts in it.....lol....
should say the glass is 6mm laminated.....hate the scratched plastic look...
speaking of paint, it'd be nice to see it repainted but I kinda like the just used look.....still undecided....
but then I'd have to repait the Bridgeport and others.....

the other mod I did was to fit a new on/off switch...the old rotary was junk and the original position was scary.....
it's all a bit Heath Robinson but it works.....wont be up to Sideways or ur standard but will be revised when it finally see's the light of day....

Mine was bought used from a father /son workshop in Colchester, the old man bought it new from the factory, early70's.
When the electrics went south they just parked it at the back and used it a storage unit....


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## Sideways (15 Nov 2022)

clogs said:


> Sideways
> has ur student a clutch or a brake....I was told u can't have both....



Mine's the L5 Clogs  
It definitely has a clutch. I don't think it has a brake although it does stop pretty quickly once you disengage the drive.

I like your mod to your student. Very effective. I'm sure my dad's old petrol rotavator had a clutch that worked in a similar way. It had a third simple pulley that pressed on the back of the V belts and tensioned them. The clutch lever just took the tension off this idler pulley to slacken the belts.


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## Pimpdriver (29 Nov 2022)

Hi Sideways,
Great right up, I have just used you photos to help me set up the tailstock on my L5, it was great to see one in bits, before I took mine to bits. I have just added a DRO to mine, works great and surprisingly cheap to do. I am mainly a metal basher and found this thread on an internet search. I am really interested in the clutch discs you had made, i would really like a set as mine are pretty worn, any chance of being able to get a set?
Eric


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## Sideways (29 Nov 2022)

Eric.
Sent you a private message. Look for the little envelope icon top right of your browser window.
If you can't see it, tell us here.
Please post some pics of your DRO upgrade here too for us all to see.
Welcome to UKW !


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## Pimpdriver (29 Nov 2022)

My L5 is probably of similar vintage to yours, but as usual, is a little different. The Clutch is the two pins type, but I ended up gluing them the faces as they are very thin and the pins wouldn't hold them properly. The main difference I can see is in the clutch lever and the fast/slow gear lever. On yours, they are hinged, I guess you lift to unlock, move, and lower to lock. On mine, they are not hinged, just simple levers.


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## Sideways (29 Nov 2022)

Do you have a serial number on yours ? It is stamped into the bed somewhere at the tailstock end and on or near the ground surfaces.
With the serial number, we can check against the list and find out when yours was made - at least to the year.
You are right about my clutch. The lever is lifted and swung. It drops into a shallow notch at the end. There is a (not very strong) spring helping to hold it down in the notch.

When you are writing a post, you'll see a blue rectangular button below your text labelled attach files. Use that to upload photos. Once uploaded, the photos will be added as attachments at the end of your post. If you put your cursor inline in your text, you can also then mouse to any of the thumbnailed images you have attached and the option to "insert image inline" will appear. Click it and the image will be inserted in the flow of text at the cursor position.

You can do this several times to place some or all the photos among your text.


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## Pimpdriver (29 Nov 2022)

Harrison L5 DRO.
I had some spare time on the last bank holiday, so I fitted the Vevor 2-axis DRO I bought earlier in the year for £117. This consisted of the Display/Control Box and a long and short glass scale. They came with lots of brackets, but as usual, the 'Universal' fit - didn't. The Long Axis scale was quite easy to fit, it was a bit long, but I just attached it to the back of the Bed. The Cross-slide scale was a bit trickier, it needed a bit of aluminium machining to space it away, and careful fitting to still allow access to the saddle and cross-slide lock screws. The reader for the Long Travel was fitted using some aluminium channel i had off the back of the saddle, and the cross-slide one was fitted on another aluminium bracket screwed into the top of the saddle.
The Scales came with aluminium protection covers, again, the long travel one fitted straight on. The cross-travel one just would not fit, so I ended up making one. The only mod to the Lathe I had to do (apart from drilling and tapping lots of holes) was to turn down the o/d of the wheel (handle) of the tool-post slide & m/c a flat on it so the it would go over the cover.
The readers just plugged into the Box, switched it on, and it all just worked.













I only have pictures with covers in place. and as you can see, the lathe is in 'used' condition.

Cheers

Eric


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## Sideways (29 Nov 2022)

Excellent !
The lathes look v similar vintage.
The DRO must make it much easier to use. Do you find it as accurate as you expected ?


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## Pimpdriver (30 Nov 2022)

Its taken a bit of learning, but i'm really happy with it. Being able to make cuts on the long travel and know where you are, makes it so much easier.
I have just machined some engine liners on the lathe, using a borrowed mandrel, and once I got the hang of it - it was brilliant.




I found it pretty accurate, but once I locked the cross-slide before final machining. This would effect the readout, so you had to stop 0.04 mm before the dim required, and then tighten the cross-slide lock screw to get to the final figure. 

I'll look for the number tomorrow

Eric


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## Fergie 307 (30 Nov 2022)

Pimpdriver said:


> My L5 is probably of similar vintage to yours, but as usual, is a little different. The Clutch is the two pins type, but I ended up gluing them the faces as they are very thin and the pins wouldn't hold them properly. The main difference I can see is in the clutch lever and the fast/slow gear lever. On yours, they are hinged, I guess you lift to unlock, move, and lower to lock. On mine, they are not hinged, just simple levers.


The fixed levers are the older design. I think the hinged ones were an extra cost option for a time, then became standard in about the mid fifties.


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