Subject says it all, I need to find at least 3 5/16-22 allen head cap screws, about 1.5" long. I do NOT need 5/16-24 screws and this is not a misprint, I really need 5/16-22. I think it is some english size, it's to fit the back of an english 3-jaw lathe chuck.
Nick, is it possible that this is an 8mmX1.25 thread pitch metric screw?
RJ
Metric and Multistandard Corp, in Elmsoford NY.
Jim
That would come closer to fitting a 20 TPI gauge, not a 22 TPI one. I come up with 1.1545 mm pitch as a direct conversion of 22 TPI. I agree that the 8mm is quite likely, and am now tempted to look in _Machinery's Handbook_ to see whether they document a 1.15 mm pitch.
Nope! And a quick check in the unified threads chart sows 5/16" fasteners at 18, 20, 24, 27, 28, 32, 35, 40, and 48 TPI, but no 5/16-22 listed at all.
If you really need that, perhaps it is time to single-point one on your lathe -- if you have something else to hold it while you mount the chuck.
But what were you measuring to get this 22 TPI figure?
Good Luck, DoN.
I was measuring a bolt that fit the internal threads, but I need an allen bolt.
I was measuring a bolt that fit the internal threads, but I need an allen bolt.
O.K. You've now got a pointer to what the thread origin is, thanks to another followup.
Good Luck, DoN.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.