Scratch Built Metalworking Lathe.

[niall Y]

I've recently posted a few enquiries regarding the tapered bearings on my lathe. The fact that it had been scratch -built ( not by me I hasten to add ) seemed to present a few initial difficulties when trying to identify what replacement bearings to order. However, it is all done and dusted now, with the new ones fitted. And, it's working better than ever............

For those who might be a bit curious about what a lathe of this sort , looks like I thought I would post a few photos.

 

[Against_The_Grain]

Did you buy it locally?

 

[niall Y]

Did you buy it locally?

Better than that, my son was given it! We have since fitted a new motor, and replaced the plate it was bolted to. Also fitted a VFD so we can get slower speeds' I believe it had been the makers "pride and joy" and he wanted it to go to someone who would use and appreciate it.

 

[clogs]

glad u got it fixed up.....well worth the effort....

if ever u replace them again try and use a bearing like this and on both ends of the main shaft if poss.....

they are actually rear wheel bearing used on most modern cars....many sizes available....sealed for life.....the outter race is pressed or Locited into the housing....
u will see the inner race is split.....they are tightened up by a biggish nut giving no play and a lot of shaft support....u cant really overtighten them....
plus u never have to adjust them....remember they hold up a car/1 ton plus and will easily do 100mph.....
so u will never overload it.....
I have used them on several projects but not a lathe..
I will be useing them on my home made 0.5m thickness sander......
if u want strength and accuracy these are a good way to go...

 

[Against_The_Grain]

Better than that, my son was given it! We have since fitted a new motor, and replaced the plate it was bolted to. Also fitted a VFD so we can get slower speeds' I believe it had been the makers "pride and joy" and he wanted it to go to someone who would use and appreciate it.

The only reason I asked is that many of the boys up at the RAE in Aberporth would make things like that after hours way back in the day, usually getting paid overtime for doing it as well! I've heard a few stories of the things that would get built there using the RAE's stock and parts and this lathe wouldn't be the most outlandish, the managers would leave at 5 PM on the dot, and all the apprentices and employees that were still there would pull all manner of projects out from hiding places.

 

[niall Y]

Hmm. ............. It does have that feel about it . The welding of the 3/4" plate is very neat and the spindle has been beautifully turned to shape. The important bits have obviously been made where there was access to large machinery and folk with some pretty good skills. Judging by the colour alone it certainly has a 60's, 70's vibe about it,
And to cap it all - we are not far from Aberporth

 

[Fergie 307]

glad u got it fixed up.....well worth the effort....

if ever u replace them again try and use a bearing like this and on both ends of the main shaft if poss.....View attachment 164824
they are actually rear wheel bearing used on most modern cars....many sizes available....sealed for life.....the outter race is pressed or Locited into the housing....
u will see the inner race is split.....they are tightened up by a biggish nut giving no play and a lot of shaft support....u cant really overtighten them....
plus u never have to adjust them....remember they hold up a car/1 ton plus and will easily do 100mph.....
so u will never overload it.....
I have used them on several projects but not a lathe..
I will be useing them on my home made 0.5m thickness sander......
if u want strength and accuracy these are a good way to go...

Not sure I agree with this. These bearings are designed to have a very small amount of play. If you grab the wheel of a car fitted with them, with the wheel raised off the ground, it is normal to be able to detect a tiny amount of play. So they would be excellent for something like a drum sander, as Clogs says they will take a huge load at high speed all day long. But I would think less so for something like a metal working lathe, where any play is undesirable. Probably be a very good choice for a woodworking lathe, where the very small play would be unimportant. If you look at many later metalworking lathes, they use very high spec taper roller bearings that are actually pre loaded, so for all intents and purposes, no play in the bearings whatsoever. Gamet bearings of this type are common on a lot of machines, and are several hundred quid a set. Many earlier ones use lower spec taper rollers, like the timken ones on this machine, where you adjust them to just eliminate play with the machine at working temperature. Bearing in mind that for a metal working lathe you want the spindle run out to be as near to zero as you can get. My old Harrison uses the Timken type bearings, and the run out is too small for me to be able to measure it with anything I have. These bearings are usually splash lubricated on a factory lathe, clearly not an option in this case. Here I would probably go for a moly grease, as used in car CV joints. Always interesting to see these home made machines. Some can be pretty awful. Others, and this looks the part, can be surprisingly accurate and do some good work.

 

[niall Y]

Not sure I agree with this. These bearings are designed to have a very small amount of play. If you grab the wheel of a car fitted with them, with the wheel raised off the ground, it is normal to be able to detect a tiny amount of play. So they would be excellent for something like a drum sander, as Clogs says they will take a huge load at high speed all day long. But I would think less so for something like a metal working lathe, where any play is undesirable. Probably be a very good choice for a woodworking lathe, where the very small play would be unimportant. If you look at many later metalworking lathes, they use very high spec taper roller bearings that are actually pre loaded, so for all intents and purposes, no play in the bearings whatsoever. Gamet bearings of this type are common on a lot of machines, and are several hundred quid a set. Many earlier ones use lower spec taper rollers, like the timken ones on this machine, where you adjust them to just eliminate play with the machine at working temperature. Bearing in mind that for a metal working lathe you want the spindle run out to be as near to zero as you can get. My old Harrison uses the Timken type bearings, and the run out is too small for me to be able to measure it with anything I have. These bearings are usually splash lubricated on a factory lathe, clearly not an option in this case. Here I would probably go for a moly grease, as used in car CV joints. Always interesting to see these home made machines. Some can be pretty awful. Others, and this looks the part, can be surprisingly accurate and do some good work.

You make some interesting observations in the above comments. I have mixed feelings about the lathe, but, I have to grudgingly admit that " it's not too bad really"

As I have mentioned before it is by no means as sophisticated as my old Drummond Round Bed, but at least it is useable It has its drawbacks, most of which probably spring from the initial design stage.

The motion of the carriage is by the use of a rack and pinion ,with no screw thread in sight. So, no automatic travel of the carriage, and no possibility of cutting screw threads.

The cross-slide is not fully adjustable, either for taking up the slack due to wear, or, canting it to an angle, to allow for the easy cutting of small tapers. The former has led to me having to apply shims ( a couple of sections of hack-saw blade) to stop play in the tool post.

The tailstock is a two part assembly, with the top part bolted to the base that slides along the rods forming the bed. This must have let to some inaccuracies with alignment of the centres, as there are a couple of shims sandwiched in between.

Of course this isn't a problem if left well alone. Though I have taken to removing it to allow me access for a drilling jig that allows me to bore out long wooden tubes. So this does work to my advantage. After this I do have to realign the the tail and head stocks with a "lathe centre alignment tool".

 

[J-G]

As is so often said but seldom considered relevant, knowing your machine (whatever it is) is the most important aspect in any workshop. I know my machines and often stretch them to their limits in both directions - sometimes well beyond the manufacturers claims -

In the past I have had access to a Matrix Nº50 Jig Borer with a Hilger & Watts Optical system in a temperature controlled environment on which I could rely on positional accuracy to 0.0001" (it was that long ago!) - There is no way I can get that on my Warco Mill but I do read the dials by interpolating between the dial marks to at least aim for the next magnitude. When designing a component that will be manufactured on my CNC machine, I draw it to 6 figure accuracy but don't expect to achieve that in reallity - but at least I aim for it

By knowing that you need to 'shim' the cross-slide or tail-stock you are doing the best you can with what you have.

 

[Jameshow]

The only reason I asked is that many of the boys up at the RAE in Aberporth would make things like that after hours way back in the day, usually getting paid overtime for doing it as well! I've heard a few stories of the things that would get built there using the RAE's stock and parts and this lathe wouldn't be the most outlandish, the managers would leave at 5 PM on the dot, and all the apprentices and employees that were still there would pull all manner of projects out from hiding places.

CPD obviously!!

 

[Fergie 307]

As is so often said but seldom considered relevant, knowing your machine (whatever it is) is the most important aspect in any workshop. I know my machines and often stretch them to their limits in both directions - sometimes well beyond the manufacturers claims -

In the past I have had access to a Matrix Nº50 Jig Borer with a Hilger & Watts Optical system in a temperature controlled environment on which I could rely on positional accuracy to 0.0001" (it was that long ago!) - There is no way I can get that on my Warco Mill but I do read the dials by interpolating between the dial marks to at least aim for the next magnitude. When designing a component that will be manufactured on my CNC machine, I draw it to 6 figure accuracy but don't expect to achieve that in reallity - but at least I aim for it

By knowing that you need to 'shim' the cross-slide or tail-stock you are doing the best you can with what you have.

You are so right. I learned an enormous amount pushing my old, and rather flexible, ML4 well beyond what it was really designed to do. You have to be so much more aware of having the correct profile on the tools, and them being really sharp etc. Speeds are also far more critical. But once you know it's foibles you can do surprisingly accurate work. You really learn how to work with the machine to coax the best out of it, stands you in good stead when you move on to something bigger and better. I still use it regularly, although nowadays only for light stuff like plastic. Having been brought up with bigger machines, but never having had the space for one myself, getting the old Harrison was a joy. Many home made machines I have seen have clearly been a work in progress, where they have been modified or partly rebuilt, presumably because the builder though of a better way of doing something. So the OP will probably end up making changes to it to rectify certain shortcomings, depending on what it is to be used for. At least it looks reasonably solid which is a good start, although the swing looks a little optimistic for the likely rigidity of it, but that does potentially give you Some height to play with in maybe adding a cross slide, for example

 

[Fergie 307]

You could do worse than looking at something like a unimat sl for inspiration as to how you might improve it. Broadly similar design with the twin bar bed, just on a much smaller scale, but essentially very simple machines. First thing I would probably want to do would be to introduce a leadscrew for the carriage. Must be very difficult to get a really good finish having to move it using a rack. Having a huge selection of feed speeds is a great feature of the bigger lathes. I am probably a bit sad, but have never tired of the satisfaction of pulling a lever and watching the hand wheel going round as the machine does it for you

 

[J-G]

something like a unimat sl for inspiration

Oddly enough, I have one that could be available for sale

 

[Against_The_Grain]

Hmm. ............. It does have that feel about it . The welding of the 3/4" plate is very neat and the spindle has been beautifully turned to shape. The important bits have obviously been made where there was access to large machinery and folk with some pretty good skills. Judging by the colour alone it certainly has a 60's, 70's vibe about it,
And to cap it all - we are not far from Aberporth

I dread to think how expensive those bed bars would've been back then, they look to be precision ground round bar, most likely silver steel. I have some ashtrays that were made in Aberporth that were made from 4" diameter brass bar and about 2" tall, possibly made from bar ends but still astronomically expensive stuff.

A common joke amongst them was the "Secrets Act" they had to sign was purely in place to stop the public from knowing how much of their money was thrown down the drain.

 

[Fergie 307]

Oddly enough, I have one that could be available for sale

I have one, which I have modified with a bigger variable speed motor. Nice little machine.