Good Thread Die Set?

Titanium · January 27, 2018

About 2 mouths ago I got myself a Unimate 3 lathe and I've really been enjoying playing around with it. Now I'd like to have a go at making screws for watches and was wondering if anyone knows of a good set or source of mini dies, thread gauges and the inserts I will need for lathing nonstandard threads?

Any help would be appreciated. Thanks.

rodabod · January 27, 2018

I can recommend the 31 piece HSS watchmakers set which comes branded under many names. I've cut stem threads and made screws with mine and it's incomparable to the cheap Indian carbon-steel taps and die plates which you get.

khunter · January 27, 2018

All I can say is good luck. With American pocket watches alone there are literally dozens of thread pitch/diameter combinations, and that's just with one manufacturer. Swiss or more generally European will probably be more metric based but there again, each manufacturer probably has their own specific sizes. Threading a screw hardly bigger than a grain of sand in some cases (jewel settings, small wrist watches, etc) would present even more challenges. If you have any luck let us know!

khunter · January 29, 2018

On 1/27/2018 at 12:26 PM, rodabod said:

I can recommend the 31 piece HSS watchmakers set which comes branded under many names. I've cut stem threads and made screws with mine and it's incomparable to the cheap Indian carbon-steel taps and die plates which you get.

If it's the metric set that I found in searching it would be of no use for American pocket watches, here's an image of page 1 of 8 of screws just for Elgins, and they are all in inches. Some jewel setting screws are 480 tpi, and some on this page are above 300. My guess is old time screws were rolled, as modern mass produced screws are, then cut to length and then the head and slot were formed last. I see no other way to mass produce such small pieces individually. Occasionally I have seen Elgin tap sets on ebay, and they sell for a mint when they appear.