The Home Machinist!

(ALL)
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A Method of Cutting Very Fine Screws,1790 (7p)

(80tpi -110tpi – 120tpi – 140tpi) (Amazing for 1790)
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https://archive.org/stream/jstor-300786 ... 0/mode/1up
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https://archive.org/download/jstor-3007 ... 078670.pdf
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Enjoy

Ken.

Interesting read, a bit difficult to read with the ƒ's instead of the "s"
And there is this for those of us that wondered why like me , ƒ instead of S was used
in some of the words - http://en.wikipedia.org/wiki/Long_s

Wake up, thread!!
Has anyone fashioned such a thread cutting device? I think that project would be very interesting...

Not I said the little blue hen.

if I need a screw of that size, I will purchase it from someone that is in the business of screw making.

One of the advantages of modern society...we do not have to constantly re-invent the wheel.

For anyone interested in small thread pitches with high tpi numbers Jerry Kieffer who I'd rate as among the top 10 model engineers in the world did a fairly extensive and very good article in the HSM magazine around 1990 - 2000? about making your own taps and dies for extremely high thread count 150-350 ++ tpi using little more than a Shereline lathe with it's thread cutting attachment and a set of shop made change gears to allow a Shereline lathe to cut those fine pitches. Jerry also isn't one to do any job half way and used a Glendo Accu - Finish hone to sharpen if my memory isn't faulty a Micro 100 braised carbide tool to single point the taps before hardening. Then used the hardened taps to build the required dies and hardened those. For anyone who's priced high thread count taps and dies such as the older imperial instrument threads and today's metric series of standard instrument taps you'll know why he built his own. Shereline some years ago use to show one of Jerry's bolts in there advertisment's in HSM and I recall it's threaded diameter was only .010" with about 350 tpi. Some of them were used on Jerry's more than tiny scale model of a working Corliss.
https://www.craftsmanshipmuseum.com/Kieffer3.htm for pictures of that engine. Working to those small scale sizes is more than challenging to state the obvious.