On 09/23/2010 11:18 PM, Ted Frater wrote:
Doug Miller wrote:
In article , "J. Clarke"
wrote:
On 9/22/2010 7:45 PM, Tim Wescott wrote:
On 09/22/2010 04:42 PM, Doug Miller wrote:
In , "J.
wrote:
On 9/22/2010 6:58 PM, Carla Fong wrote:
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...
Have you tried an M14x2 in it? Nominal inch dimensions .55
diameter and
12.7 tpi?
Anything "pre 1900, American-made" is vanishingly unlikely to have
metric
threads.
Unless, perhaps, it was built by a French family displaced by Royalists
after the revolution.

My bet is on 1/2-12.
I didn't say I thought it was a metric thread, I said try an M14x2.0.

Which is of course a metric thread...

Maybe it will fit,

.. 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.

maybe it won't. If it won't, you're out

When was the last time you succeeded in inserting a 0.55" bolt into a
0.50" hole?

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.

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?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html