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What to use on my Sherline mill to round off pinion wire leafs

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Chris TickTock13/12/2019 17:27:07
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Hi, I am getting better on my Sherline lathe but work to be done regarding my Sherline Mill. Later next year I hope to concentrate on the mill but until then can anyone suggest a possible workaround for this issue:

pinion wire comes in many diameters if you are lucky enough to find it but sometimes you may have the correct wire in terms of number of leafs but the wrong diameter. I am told it is possible to reduce the diameter and I can easily do this on the lathe. However you will be left with square edges that need rounding off. There are special cutters I am sure but until I get there is there something more prosaic like a burr that could be used on my mill for this small job if I had to do it?

Chris

Nigel Graham 213/12/2019 17:56:21
720 forum posts
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I am not a clock-maker but looking at that in general terms, unless the radius is critical simply grind a small concave form tool from high-speed steel.

Another approach for more definite results is to make a form tool by drilling a hole through a piece of gauge-plate, cutting the corner off and heat-treating to suit.

Chris TickTock13/12/2019 20:39:13
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Posted by Nigel Graham 2 on 13/12/2019 17:56:21:

I am not a clock-maker but looking at that in general terms, unless the radius is critical simply grind a small concave form tool from high-speed steel.

Another approach for more definite results is to make a form tool by drilling a hole through a piece of gauge-plate, cutting the corner off and heat-treating to suit.

Thanks Niigel, I get your first suggestion infact the method I will be using to make a brass wheel next year relies on making such a tool you first mention.

However unfortunately I cannot mentally get an image of the 2nd concept you suggest maybe someone could clarify this.

Chris

roy entwistle13/12/2019 21:32:07
1225 forum posts

In 65 years clock making I've never found a source of pinion wire. How do you know the diameter is wrong?

Roy

Chris TickTock13/12/2019 21:41:27
563 forum posts
39 photos
Posted by roy entwistle on 13/12/2019 21:32:07:

In 65 years clock making I've never found a source of pinion wire. How do you know the diameter is wrong?

Roy

Hi Roy, this is hypothetical in as much as if you sourced a length of say 10 leaf pinion wire at say 9mm dia then needed for another job 8.6 mm you could turn the diameter down on a lathe but need to correct the leaf profile. My source was just a one off lot of new old stock. I suspect making your own is the norm unless you know different?

Chris

roy entwistle13/12/2019 21:57:36
1225 forum posts

The Module or DP would be wrong . you can get away with .5 Mod but that's about it How do you know what the diameter should be? If it's just one pinion then I would use a file

Roy

speelwerk13/12/2019 22:46:42
372 forum posts
5 photos
Posted by roy entwistle on 13/12/2019 21:57:36:

The Module or DP would be wrong . you can get away with .5 Mod but that's about it How do you know what the diameter should be? If it's just one pinion then I would use a file

Roy

Never tried and perhaps in a clock you can get away with .5 Mod, but is it not .05 you mean since in a musical box governor it would wear out the corresponding wheel in record time. Niko.

Michael Gilligan13/12/2019 23:22:51
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To the best of my knowledge: traditional Horological pinion wire was never intended to be used ‘as supplied’ and will always need some shaping and finishing ... i.e. it is a convenient ‘make from’ material. Skimming it down to size will just mean that you need to do more of the same.

Very happy to be proved wrong !

MichaelG.

JasonB14/12/2019 07:11:09
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Posted by Chris TickTock on 13/12/2019 20:39:13:
Posted by Nigel Graham 2 on 13/12/2019 17:56:21:

Another approach for more definite results is to make a form tool by drilling a hole through a piece of gauge-plate, cutting the corner off and heat-treating to suit.

However unfortunately I cannot mentally get an image of the 2nd concept you suggest maybe someone could clarify this.

I would imagine something like this either grind up an HSS tool or drill/file some HCS to profile and then make a simple holder or even use a flycutter if you have one then you can make whatever shape you like- just the tips or the whole tooth form.

Couple of photos from my Milling for beginners series

photo 90.jpg

photo 89.jpg

roy entwistle14/12/2019 08:40:01
1225 forum posts

Speelwork Quite correct I did mean 0.05 Blame it on a senior moment blush

MichaelG Again quite correct. I've only seen pinion wire once and that was in the now defunct clock museum at

Prescot. I believe that it was made by drawing so could only be crude and possibly only made in watch sizes

Look up Wig-Wag polisher for interest

Roy

Michael Gilligan14/12/2019 08:58:50
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Largely ‘academic’ for most of us, because of the cost, but

Here, for reference, is Thornton’s page: **LINK**

https://ppthornton.com/product/pinion-cutter-2/

Note the range of sizes and counts surprise

The standard profile is described in BS 978 part 2, but obviously a reasonable approximation will work.

MichaelG.

.

P.S. ... The lantern pinion is an admirable alternative, both technically and financially.

Michael Gilligan14/12/2019 09:12:53
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From the ninth edition, 1896, of Briitten’s ‘Handbook Dictionary and Guide’

.

 

02b40730-0f0d-49b1-8359-8037749b6e94.jpeg

.

MichaelG.

.

Edit: Just found this : https://youtu.be/VHysXT7RaIM

... and don’t forget to watch Clickspring’s masterclass : https://youtu.be/XkJJid3_bhg

Edited By Michael Gilligan on 14/12/2019 09:30:04

Michael Gilligan14/12/2019 09:48:20
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Posted by roy entwistle on 14/12/2019 08:40:01:

[…] I've only seen pinion wire once and that was in the now defunct clock museum at

Prescot. I believe that it was made by drawing so could only be crude and possibly only made in watch sizes

.

From Chris’s other recent thread, it appears he has some vintage stock of 8mm diameter pinion wire ... which would be a useful size for clockmaking.

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=147933&p=1

MichaelG.

JasonB14/12/2019 10:10:07
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From your scan that's an interesting and simple way to relieve a small cutter and the "pusher" is useful too as a standard Ctr often stops you getting in close, bit like a half ctr in the tailstock.

speelwerk14/12/2019 10:20:47
372 forum posts
5 photos

What I found on clock fairs is too small for my use but being cheap just bougth it. This older thread is perhaps also of interest **LINK** . I cannot see myself acurate making large correctings to pinion leafs with a file, if needed it is better to make a new one the correct size. Niko.

Edited By speelwerk on 14/12/2019 10:21:40

Edited By speelwerk on 14/12/2019 10:24:44

blowlamp14/12/2019 10:22:55
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1396 forum posts
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I think pinion wire is quite often filed/abraded and then polished to final form.

Michael Gilligan14/12/2019 10:40:38
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Posted by JasonB on 14/12/2019 10:10:07:

From your scan that's an interesting and simple way to relieve a small cutter and the "pusher" is useful too as a standard Ctr often stops you getting in close, bit like a half ctr in the tailstock.

.

There was a lot of innovation in the American watch and clock industry. yes

... hence importance of the little book that linked in the ‘Build a watchmakers lathe’ thread

[quote]

For background reading, you will probably find no better reference than this: **LINK**

https://archive.org/details/watchmakerslathe00good

[/quote]

MichaelG..

Michael Gilligan14/12/2019 10:52:45
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Posted by Michael Gilligan on 14/12/2019 08:58:50:

.

The standard profile is described in BS 978 part 2

.

Not sure if this **LINK** really counts as an ‘extract’ but anyway ...

MichaelG.

Michael Gilligan14/12/2019 12:26:09
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16202 forum posts
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Clever chap, Duane H. Church star

**LINK**

https://patentimages.storage.googleapis.com/6a/19/01/dc93bfb577df05/US476953.pdf

MichaelG.

Chris TickTock14/12/2019 13:33:59
563 forum posts
39 photos

Really grateful for all help will study all posts carefully and report back.

Chris

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