Need oddball bolt: 1/2" x 12 TPI

Hi everyone -
I've got a repair project on an ancient (pre 1900, American-made)
Chandler and Price guillotine paper cutter that I'm short a couple of
odd bolts. 1/2" diameter, 12 TPI. (Yes, 12, not 13)
Before I turn them out on the lathe, does anyone by any chance have
anything like this (about 3/4" long, or longer and I can cut them off)
they'd like to part with? I need three of them...
Thanks in advance...
('reply to' is spam-trapped, use the address below)
Carla
carla (at) 97381 (dot) com
A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete fools.
Reply to
Carla Fong
Loading thread data ...
Have you tried an M14x2 in it? Nominal inch dimensions .55 diameter and 12.7 tpi?
Reply to
J. Clarke
that's a standard Whitworth thread
Reply to
Bill Noble
Anything "pre 1900, American-made" is vanishingly unlikely to have metric threads.
Reply to
Doug Miller
Unless, perhaps, it was built by a French family displaced by Royalists after the revolution.
My bet is on 1/2-12.
Reply to
Tim Wescott
That's a British Standard Witworth or BSW thread. You can find the bolts in the USA here:
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Reply to
anorton
I was going to say "Not if it was pre-1900" -- but Whitworth was a standard by 1841!!!
Double-check the thread form, though -- just because the threads are pointy doesn't mean that they're 60 degree (or 55 degree, for that matter).
Reply to
Tim Wescott
...
I thought flashing/blinking text was annoying, but the rotating bolts there are MUCH worse. I would have to be absolutely desperate to order anything there.
Bob
Reply to
Bob Engelhardt
I didn't say I thought it was a metric thread, I said try an M14x2.0. Maybe it will fit, maybe it won't. If it won't, you're out
Reply to
J. Clarke
The idea was it might be close enough to work.
Reply to
Joe Pfeiffer
Which is of course a metric thread...
.. and if it fits, then the hole it fits into is *also* threaded with a metric thread -- which, as I said, is vanishingly unlikely for anything made in the United States in the 19th century.
When was the last time you succeeded in inserting a 0.55" bolt into a 0.50" hole?
Reply to
Doug Miller
The bolt's bigger than the hole.
Reply to
Doug Miller
Ive just looked up my Zeus thread chart, and as I thought, what your after is 1/2in B S whitworth threaded bolts. Ive plenty!! but of course the snag is im in te UK where BSW threads were used and still are on old machinery repair work. Im pretty sure I could find some to match your need , and they would be free to you apart from the postage from the UK. Any help? to you? The Chandler and Price guillotine may well be UK made tho. Frater In Dorset UK.
Reply to
Ted Frater
Actually, according to the Wikipedia article on Whitworth, it was used in the US until the early 1900's, when we adopted our own standard. IIRC, we changed the thread form from a pointy 55 degree to a flat-top 60 degree, but for the most part the 'merican coarse thread sizes match Whitworth -- with the exception of 1/2 inch, where we chose 1/2-13 instead of 1/2-12.
Mebbe someone on the committee had been beaten up by a lathe maker at some point, or just thought 13 tooth gears were lucky?
Reply to
Tim Wescott
1/2"X 12 TPI is British Standard Whitworth. I have no idea where you could find them in the U.S. If you decide to turn them, note that the thread angle is 55 degrees not 60.
Reply to
Grumpy
whitworth taps are commonly available - I happen to have some because of british cars, but they are not at all hard to find - and ebay is a source for them cheap -
Reply to
Bill Noble
They may not be Whitworth. I measured a tap I have here that's marked 1/2-12 USF and it's definitely a 60 degree thread. I've no idea what USF stands for -- perhaps it's related to the old USS (United States Standard) thread.
I repaired an old 36" bandsaw that used 1/2-12 fasteners and had to single point several replacement bolts. The saw was probably late 19th century. Old enough that the wheels had steel spokes and steam bent oak rims.
Reply to
Ned Simmons
I see it in Machinery's Handbook - defined as :
Designating UNS Threads.=97UNS screw threads which have special combinati= ons of diameter and pitch with tolerance to Unified formulation have the basic f= orm=20 designation set out first followed always by the limits of size.
The pitch diameter tolerances used in Table 3 for all classes of the UNEF= ,=20 12-UN, 16-UN, 20-UN, 28-UN, and 32-UN series and the UNS series, are base= d on a=20 length of engagement of 9 pitches and are applicable for lengths of engag= ement=20 of from 5 to 15 pitches.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net=
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Originator & Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufk> >
Reply to
Martin H. Eastburn
Reply to
giuseppe4892

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