# Reducing the diameter of steel rod without a lathe?



## sploo

Warning: totally ignorant metalworking noob questions ahead...

I need some steel rod (approx 8cm length) turned to approximately 7.3mm in diameter, with the last ~1cm turned down to 6mm so I can use an M6 die cutter. I don't own a lathe of any kind.

I've made a set of pillow blocks with 8mm bearings so I can support a length of rod without too much whip or "wobble", and I could then spin it vertically on a drill press or horizontally on a bench using a power drill.

I was then planning on grinding it down to the desired diameter by using some coarse abrasive on a block, but it occurs to me that a metalworking lathe will have some form of cutter for this task. I probably could rig up a holder for such a tool to move it across a workbench. Am I essentially after something like this: http://www.axminster.co.uk/tungsten-car ... 8mm-536001


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## blackrodd

Sounds like you have the basics to hand, bearings, steel etc.Those carbide tools would likely be difficult to mount and probably leave ridges, scratches, etc.
I suggest you set up the power drill on slow and using a flat file and once started, a gauge ending up at you're required 7.3mm Steady and carefull should win the day.
Regards Rodders


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## MCB

sploo":34w9fola said:


> Warning: totally ignorant metalworking noob questions ahead...
> 
> I need some steel rod (approx 8cm length) turned to approximately 7.3mm in diameter, with the last ~1cm turned down to 6mm so I can use an M6 die cutter. I don't own a lathe of any kind.



Why do you want to use an M6 die?

Why NOT use an M8 die on 8mm diameter rod?

Could you redesign the job to use studding? or an 80mm long M6 grub screw?

MC


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## adidat

I could do it on my lathe? 

Adidat


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## sploo

blackrodd":8an7wcai said:


> Sounds like you have the basics to hand, bearings, steel etc.Those carbide tools would likely be difficult to mount and probably leave ridges, scratches, etc.
> I suggest you set up the power drill on slow and using a flat file and once started, a gauge ending up at you're required 7.3mm Steady and carefull should win the day.
> Regards Rodders


Thanks. Maybe my Heath Robinson contraption isn't so crazy after all then :wink: 

I would very much like a small metal working lathe, and this sort of thing comes up occasionally. I would also like the space for one!


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## sploo

MCB":3dvj31zf said:


> Why do you want to use an M6 die?
> 
> Why NOT use an M8 die on 8mm diameter rod?
> 
> Could you redesign the job to use studding? or an 80mm long M6 grub screw?


It's for a missing fence rod on a Stanley #78 rebate plane. I have the fence itself, which appears to need a ~7.3mm rod, but the end of the rod screws into the body of the plane, which appears to be M6.

It may be that the original rod is 9/32" (7.14mm) but the thread into the body is definitely not 1/4" UNC (an M6 bolt fits reasonably well). The fence is locked using an M5 bolt, and indeed M5 is used for the depth stop, so I am assuming it's mostly metric.




adidat":3dvj31zf said:


> I could do it on my lathe?


Thanks. Another member already generously gave me a knurled screw he'd made for another project, so I'd feel a bit cheeky taking more time from others. I'll probably have a go at it myself for the time being. One day I'm going to have to bite the bullet on a lathe (and learn how to use it, obviously)!


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## MCB

sploo":2ojf1o53 said:


> I would very much like a small metal working lathe, and this sort of thing comes up occasionally. I would also like the space for one!



I suspect that many of the men reading this would also like a small metal working lathe (and a bigger shed)

I am tempted by a Peatol/Taig and would like to pick one up at the right price - but unfortunately don't know where to look!!

Happy New Year

MC Black


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## blackrodd

sploo":2iftkle0 said:


> blackrodd":2iftkle0 said:
> 
> 
> 
> Sounds like you have the basics to hand, bearings, steel etc.Those carbide tools would likely be difficult to mount and probably leave ridges, scratches, etc.
> I suggest you set up the power drill on slow and using a flat file and once started, a gauge ending up at you're required 7.3mm Steady and carefull should win the day.
> Regards Rodders
> 
> 
> 
> Thanks. Maybe my Heath Robinson contraption isn't so crazy after all then :wink:
> 
> I would very much like a small metal working lathe, and this sort of thing comes up occasionally. I would also like the space for one!
Click to expand...


The better chinese ones, for occasional use are well enough regarded.
I've recently bought a Unimat SL I'm told it's very good for small jobs, I've just made a handle for the tool feed, and it seemed ok.
I did buy a myford ML2 cheap from a friend, In September, which had to go in my sons workshop, too large for mine.
Most bits are dear for either, but quality doesn't seem to be a problem.
Regards Rodders


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## MCB

sploo":3obeant7 said:


> It's for a missing fence rod on a Stanley #78 rebate plane. I have the fence itself, which appears to need a ~7.3mm rod, but the end of the rod screws into the body of the plane, which appears to be M6.
> 
> It may be that the original rod is 9/32" (7.14mm) but the thread into the body is definitely not 1/4" UNC (an M6 bolt fits reasonably well). The fence is locked using an M5 bolt, and indeed M5 is used for the depth stop, so I am assuming it's mostly metric.



You may like to know that M6 is almost exactly 0BA (same pitch but different angle)

Forgive me asking but are you sure that the “M5 threads” are not BA sizes too?

Do you know where and when the plane was manufactured? Have you asked Stanley about thread sizes?

There may even be a web site for people restoring old planes!

MC


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## adidat

Well the offer stands

Adidat


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## AndyT

I expect the rod would be a standard imperial size diameter - maybe 9/32" which is 0.2812". (7.3mm is 0.2874".)

So if you can find a bit of that, you still need to file a reduced diameter spigot at the end. This just needs a vice, a file, and two washers as explained here by the ever resourceful Robert Wearing:


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## Harbo

The Unimat SL and later 3 were made in Austria -the 4 is Chinese.
Most add-on parts and tooling are interchangeable.
They are very compact - I've had one for a number of years and find it extremely useful:






Rod


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## sploo

MCB":1ziqn90y said:


> You may like to know that M6 is almost exactly 0BA (same pitch but different angle)
> 
> Forgive me asking but are you sure that the “M5 threads” are not BA sizes too?
> 
> Do you know where and when the plane was manufactured? Have you asked Stanley about thread sizes?
> 
> There may even be a web site for people restoring old planes!


Oh yeah - lots and lots (and lots) of sites regarding old planes. Difficult to date this one due to little use/the fact it's been sitting in a drawer in my dad's garage for years. Not "proper" old, but probably 10+ years.

I had to look up BA thread as that's a new one for me.

I found a thread on another forum hinting that 9/32" may be right for the rod - though given how much a 7mm metal bit wobbles in the hole I'd worry it wouldn't be very accurate. That same thread indicated it's possibly 1/4" 28tpi (UNF?); but Stanley are notorious for changing threads on tools over the year. That at least would explain why a 1/4" UNC bolt was a no-go, and M6 sort of worked over a short distance (assuming metric coarse => 1mm => 25.4 tpi).

M5 seems to work really well in the other holes, so I assume it's likely to be #12 (5.4864mm) as #10 (4.8260mm) may be too tight.

Given that I don't have any UNF die cutters it may make more sense just to buy this (http://www.amazon.co.uk/Stanley-Spares- ... B0015QDLE0) but I only need the rod and screw, not the fence itself.




adidat":1ziqn90y said:


> Well the offer stands


Greatly appreciated - many thanks!



AndyT":1ziqn90y said:


> I expect the rod would be a standard imperial size diameter - maybe 9/32" which is 0.2812". (7.3mm is 0.2874".)
> 
> So if you can find a bit of that, you still need to file a reduced diameter spigot at the end. This just needs a vice, a file, and two washers as explained here by the ever resourceful Robert Wearing:


That's a good technique. Filed for future use!


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## MusicMan

You can come up to Warwick and use my metal lathe and screw dies if you like. Training provided!

Keith


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## sploo

MusicMan":2zstf8fc said:


> You can come up to Warwick and use my metal lathe and screw dies if you like. Training provided!
> 
> Keith


That would be a lot of fun, and Warwick's not that far away. Not sure when I'd get a window with job + family though!

In the meantime, I found this http://www.amazon.co.uk/Piece-UNC-UNF-T ... B006B3OTZW and this https://maccmodels.co.uk/materials-meta ... -long.html ; which I guess would mean I'd only need to turn down a small section at the end of the bar before cutting a thread, and I'd have some bar left over plus an (admittedly cheapo) tap and die set. Might be worth a punt.


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## blackrodd

Harbo":1zm4pay8 said:


> The Unimat SL and later 3 were made in Austria -the 4 is Chinese.
> Most add-on parts and tooling are interchangeable.
> They are very compact - I've had one for a number of years and find it extremely useful:
> 
> 
> 
> 
> 
> 
> Rod



I think you have the best model there in a #3, as most of what you either would like or need is on it.
A tidy SL, with the 3 jaw chuck, and a dead end in the tail stock will fetch around £300, + and will not always have the milling bar and bracket, 
Which will cost £80-£100 with the rise and lower handle, return spring and washer.
The SL chucks are threaded at 1mmx12mm thread so 3 jaw and 4 jaw chucks will not interchange with any later models as they are at 1mmx14mm nor the drill chucks or dead or live ends fit the different taper.
Fitting a 12mmx1mm to 14mmx1mm adaptor each end is possible but at a loss of around an inch or 25mm between centres at 6" or 150mm.
Auto feed and threading facilities are over £100 a time plus threading dies.
So as usual one must decide from the start you're needs in any machine, as buying add on's later can be very costly.
Regards Rodders


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## Sheffield Tony

If you are lucky, a tap and die set costing £15 _might_ just last long enough to thread one piece of silver steel - you may be better buying a good die of the size you want. You might also have a small extra filing step with a thin file to relieve the thread at the shoulder, so that it screws right up (the die won't thread right to the bottom).

Are the original rods plated ? I think they were. In which case the 7.3 mm is possibly 9/32 + the plating.


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## sploo

Sheffield Tony":2b7uxl04 said:


> If you are lucky, a tap and die set costing £15 _might_ just last long enough to thread one piece of silver steel - you may be better buying a good die of the size you want. You might also have a small extra filing step with a thin file to relieve the thread at the shoulder, so that it screws right up (the die won't thread right to the bottom).
> 
> Are the original rods plated ? I think they were. In which case the 7.3 mm is possibly 9/32 + the plating.


I'll only need to thread about 1cm (~3/8") of the rod, so not too much load. I have a metric set that looks to be from the same brand/factory and it's done the job for me so far (admittedly with little use).

I don't know if the original rods were plated, but that is a good point re the diameter.


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## Sheffield Tony

To remove some uncertainty I just measured my #78; the rod is a shade over 7.1 as best as I can measure, so 9/32 most likely. The thread is definitely not metric, but looks like a 1/4". I don't have thread gauges at home. The rod is chromed, and the thread is relieved at the shoulder. As the threaded part is only 10mm ish as you said, I think I'd try Andy's file and two washer trick. Possibly finishing it off in the pillar drill to get it nicely round and make a bit of a lead in for the die.


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## sploo

Sheffield Tony":zbuzqdik said:


> To remove some uncertainty I just measured my #78; the rod is a shade over 7.1 as best as I can measure, so 9/32 most likely. The thread is definitely not metric, but looks like a 1/4". I don't have thread gauges at home. The rod is chromed, and the thread is relieved at the shoulder. As the threaded part is only 10mm ish as you said, I think I'd try Andy's file and two washer trick. Possibly finishing it off in the pillar drill to get it nicely round and make a bit of a lead in for the die.


Many thanks. That's very useful.

I've gone for a punt of some steel rods from https://maccmodels.co.uk/. There's a 9/32", but I've also ordered a 7.5mm, which I guess I could grind down slightly if the 9/32" is a hair too small. Certainly it'll be less work than grinding down an 8mm rod.

I also ordered the cheap tap and die set. With luck it'll handle cutting a 1/4-28 UNF thread.


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## rxh

I have made replacement rods for Stanley 78s. The thread is 1/4" x 28 TPI UNF.


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## sploo

rxh":3g8aezvr said:


> I have made replacement rods for Stanley 78s. The thread is 1/4" x 28 TPI UNF.


Thanks Richard. I've ordered the right die then!

I have the rods so hopefully will at least get chance to try them on the fence tonight.


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## sploo

Right, the good news is that the 9/32" rod only has a tiny bit of slop in the fence, and once locked down with a knurled screw or bolt it's sufficiently solid that I suspect the margin of error in use will be my (lack of) skill rather than the fence moving. As such, I should only need to grind down ~1cm of the rod to 1/4" for the thread - much easier than modifying a longer length.

Incidentally, I ordered a number of knurled screws from here http://www.wdsltd.co.uk/product/3333/kn ... el-wds-521. The M5 ones work perfectly on the fence (for locking the rod), so whilst I assume it'll actually be a UNF thread like the main body of the plane, it's appears to be fine.


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