Actually I believe it should be an 11/16-20 thread. A McMaster Carr no. 26005A155 @ $70.56 page 2520 is for a die that is national special (NS) thread. If that was a quote from me Stu, I’m not sure where I got that information. I did buy an 7/161-24 NS die for chasing the threads on the inverted flare line stuff.
Tiny, not sure what you had either, any fine thread metric nut close to that diameter would be a 1mm or 1.5mm pitch. There is a 1.25mm, which is the same pitch as our 20tpi but as far as I know that is not used in the diameters that would fit the generator shaft. The nominal shaft size is .6875” and the only metric threads that are at all even close are M16x1.00, M16x1.5 or M17x1.00, M17x1.5. The M16 or M17 fine threads are not produced in a 1.25mm pitch.
I don’t recall the thread Keith, was that Ken’s suggestion to switch to a 5/8-20 thread? I doubt if I would have suggested that unless the original thread was so bunged up that it couldn’t have been saved. I think I would have opted to get the correct die and chase the original threads.
I should mention that your measurement is an actual measurement and the if you check the shaft size you will find that it is .6875". The tops of the thread are often chopped off so the pulley will slip on with out messing up the thread so the nominal is 11/16" but your actuall will be less.
Denny Graham
Sandwich, IL
Last edited by Denny Graham; 04/18/2009 4:46 PM.
