Mark,

I've found it at last …

Have a look at illustration 2.21 in this book

MichaelG.

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Mark,

Sorry, I don't get your point: The picture include one drawplate hole for a six tooth pinion.

Every Horological reference That I've seen describes steel pinion wire as "drawn".

The important thing is … Pinion Wire [for Clocks] is not a finished component; it's raw material to "make from".

MichaelG.

Michael, Niko, I had a look and found a patent specific to this type of product – it is sized but it is not drawn in the conventional sense where you take a round wire and reduce it in CSA and shape as it passes from one die to another. The pinion is pre-formed by radial compression (which is how the undercuts are made possible) and then sized through a finishing die or two. Look at **LINK**

Normally you would expect to reduce CSA roughly 10% at each die and there is the problem – how do you get enough material into the flanks of the teeth and still get back to size with the undercut? The pinions without undercuts (continuously reducing tooth section) could be drawn on a conventional wire drawing rig but even these would be problematic unless the material was very easy to form. I looked at the old book drawing mentioned – I would love to see that system work for real, just getting from round to square takes enough effort and planning never mind getting pinion shapes in one pass….

Mark

Don’t know how pinion wire was actually made but material of similar shape is still made to this day for engineering components .

Three common processes :

Shaving dies – these progressively cut the shape from initially round bar .

Die extrusion – for more easily worked metals .

Simple milling for small quantities .

The pinion wire that I have seen has been a bit rough and I’d certainly want to use something better myself . Could probably make some on ordinary lathe / mill but there are several designs available for little pinion mills .

Don’t know whether clock pinions should be hardened – there are arguments for and against .

MikeW

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Roy,

Yes, I made that point to Mark .. [04/01/2014 19:00:52]

But it appears that Niko has some modern Pinion Wire that is finished profile.

See post: [04/01/2014 19:14:28]

I say "appears", because it's quite small, and detailed examination under the microscope may prove otherwise.

MichaelG.

For those interested: Here is a brief description of how traditional Pinion Wire was used.

… I still can't find a detailed description of how it was made.

MichaelG.

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Edit:   A few words about the process, here

" … as many as fifty drawings … "

Edited By Michael Gilligan on 05/01/2014 19:17:59

John,

Yes please, … I have just sent you a PM

MichaelG.

Michael, I don't know anything practical (other than what I was taught) about tube production or soft metal wire production such as copper etc. My experience is related only to spring steel products – hard drawn and rolled sections – and some limited mild steel rolling of profiles. It was all done at relatively high speeds, drawing runs from circa 600 ft/min and rolling half that speed. All the stuff we used to make was large production – a rod at a time with rods being welded together end on end and the joint cut out at the finished end (rod = 2 tonne mill stock coil – the sort of thing you see stacked on the back of trucks with the coil being some 4 ft dia. and perhaps 6 ft tall).

We would take annealed spring steel and draw it down to produce either a hard drawn (work hardened) or heat treated (either soft annealed or harden and temper) wire or process it further by rolling it in a set of opposing rolls on one or two axis simultaneously to produce trapezoids or prismatic forms along with ovals and round edge flats. Rolling and drawing is done in stages and roll sets are normally linked together in a series machine to allow multiple operations and passes as there is a limit (normally about 10% reduction of CSA) on how much work can be done at a single pass.

The material would often require HTreatment after drawing or rolling and this was also done in a continuous process – the last company I worked for used to make very high quality spring steels and I understand they were one of the last companies in the UK to provide "lead patent" wire which was quenched in lead rather than oil or air – producing the finest quality spring wire available at the time.

As an aside, we used to make oval spring wire that was some 3 x 1 mm (major/minor axis) and this was always one of the most demanding products we made. It had a very specific use….. it was formed into bra stay wires!

There is a huge amount of knowledge involved in this area of manufacture and a lot of it is propriety, if you have a specific question I would be happy to try and help but it would take a lot of time and effort to try and document the whole process.

Mark