Trouble identifying a Pullmax bolt size

[RockHillWill]

I removed one of the upper bolts that holds the lower tool holder on the P7 to see if I had a tap of the correct size. I tried a few American nuts and a couple of metric nuts that were laying around the shop and could not find one that fit. I went to Lowes and tried their 'testing' panel and could not get the threads to engage. The threads measure .497" diameter and have 12 threads per inch. I cannot find a match in the McMaster car book either.

What am I doing wrong? Or what am I looking for????

[john galt]

See reciprocating machines thread for answer:

http://allmetalshaping.com/showthread.php?t=10620

[Marty Comstock]

They are in fact 1/2-12. an odd size that used to be more common in industry.

Use new bolts 1/2-13 for your top bolts, and move the holes in the holder up, and re counterbore so you can reuse the same bolts.

[RockHillWill]

Thanks, Marty and John, that is what I was looking for. I have run into that 1/2"-12 when I have rebuilt some of the old Hit and Miss motors, but thought there was no way the same threads would show up in a Swedish machine.

Thanks guys.

[Tom Fritz]

Will, I ran in to the same problem with mine. British Witworth is the thread. 1/2-12 thread. As Marty said, convert to 1/2-13

Tom

[weldtoride]

I have a friend into the old British bikes since forever, and they have been making a strong resurgence in the bobber scene. BS was his arch-enemy at first until he conquered it.

Thread tools are readily available if you ever want to go that way. Here's one source, there are others.

http://www.mutualscrew.com/site/sear...keyword=1/2-12