ASSRA Forum - Whitworth dies to recut V thread 12-28 screws?

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Whitworth dies to recut V thread 12-28 screws? (Read 1571 times)

ohland Participating Member Offline Posts: 37 Joined: Dec 11^th, 2012	Whitworth dies to recut V thread 12-28 screws? Aug 2^nd, 2021 at 2:17pm	Print Post
	I tried the Marble's 12-28 x 1.9 upper tang screw in an original 1885 Low Wall. Started maybe half a thread, then stopped. Playing stump the chump, and I am the only one playing. Does that mean I'm winning? Am I loosing? The period table of screws for Marble's tang sight refers to "Whitworth" and 0.208-28. The actual diameter of the original tang screw is .204, but it freely screws into a Brownell Screw Checker 12-28. The Marble's modern screw is .210 and also screws into the Checker. My suspicion is the 55 degree Whitworth thread is narrower than the 60 degree V thread, and the 60 degree "V thread" of the modern screw is wider, so it is TOO big to fit into the original tapped hole in the lower 1885 tang... Looking for "12-28" and Whitworth goes down in flames. Help?


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KFW Oldtimer Offline Posts: 634 Location: Wyoming Joined: Dec 18^th, 2016	Re: Whitworth dies to recut V thread 12-28 screws? Reply #1 - Aug 2^nd, 2021 at 4:08pm	Print Post
	Need to find a copy of the Machinery's Handbook, the thread section is well covered in it for the spec's you are looking for. kw


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moodyholler Oldtimer Offline Posts: 720 Location: Blue Ridge Joined: Oct 11^th, 2005	Re: Whitworth dies to recut V thread 12-28 screws? Reply #2 - Aug 2^nd, 2021 at 6:39pm	Print Post
	Order the correct tang bolt. It is available. moodyholler


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ohland Participating Member Offline Posts: 37 Joined: Dec 11^th, 2012	Re: Whitworth dies to recut V thread 12-28 screws? Reply #3 - Aug 2^nd, 2021 at 7:17pm	Print Post
	KFW wrote on Aug 2^nd, 2021 at 4:08pm: Need to find a copy of the Machinery's Handbook, the thread section is well covered in it for the spec's you are looking for. kw I read Machinery's Handbook 25, and the Whitworth material has no easy to understand diagram of the threadform. Page 1523, sorta suggests about a BSF, 7/32 - 28, basic dia 0.2188. Another section starts on 1761, table on 1763 has a notation on the 7/32 - 28 "To be dispensed with wherever possible" It appears there was no BSF #12, instead a 7/32.


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ohland Participating Member Offline Posts: 37 Joined: Dec 11^th, 2012	Re: Whitworth dies to recut V thread 12-28 screws? Reply #4 - Aug 2^nd, 2021 at 7:24pm	Print Post
	moodyholler wrote on Aug 2^nd, 2021 at 6:39pm: Order the correct tang bolt. It is available. moodyholler Outstanding. What is the spec and where? I looked in "The Winchester Single Shot", both Vol I and II, both identify that upper tang screwas a 12-28. In vol II , page 193 there is a small illustration of a table of Marble's flexible tang sight screws for the 1885, and the size and length closest to the original upper tang screw is labelled as a Whitworth, .208 - 28 As to a modern thread, 12-28 isn't it.


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oneatatime Frequent Elocutionist Offline Posts: 4465 Location: Rocky Mountains Joined: Oct 30^th, 2011	Re: Whitworth dies to recut V thread 12-28 screws? Reply #5 - Aug 2^nd, 2021 at 7:39pm	Print Post
	This is the one Marble says is for the original 1885s. Brownell's listing 579-000-120WB Marlin 1894 Tang Sight Screw Set .167" Black Mfr Part: 995021


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ohland Participating Member Offline Posts: 37 Joined: Dec 11^th, 2012	Re: Whitworth dies to recut V thread 12-28 screws? Reply #6 - Aug 2^nd, 2021 at 8:10pm	Print Post
	Brownell's customer support 10-36 by 0.355" OAL and 12-28 by 2.235" OAL. Brownells from Montezuma, IA I need to contact Marbles again.


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