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Re: Thread size

Posted by Dick Hosmer on Sunday, 16 May 2010, at 10:06 a.m., in response to Thread size, posted by Ernie on Sunday, 16 May 2010, at 9:05 a.m.

No, most, if not all, SA screw threads are 26 tpi, of various diameters.

I believe this was our answer to the 1mm (25.4 tpi) pitch of the screws on the French muskets, from which we copied extensively, while setting up arms production in the final years of the 18th century. I SUSPECT that the difference between the two pitches was considered negligible at the time, and, given the existing tolerances, they would probably have interchanged, in most cases, at any reasonable engagement depth.

Some people have reported using 8-32 screws, but I'd guess that to be pretty unsatisfactory. From doing some digging, I discovered that the British bicycle industry once used some 26 tpi screws.


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