Hi,
I need to make an adapter for this rotary tool but the thread has me stumped:
The scale is 1/32 and my lying eyes say the pitch is ~31.5 threads/inch. Converting to metric, 1.279 threads/mm. The diameter is 5/16 inch, 7.9375 mm.
The diameter reads SAE but I can't find any standard thread that matches this threaded shaft. The problem is my adapter needs to screw on the shaft but this does not look like any standard tap would work. I need a tap to make the part.
Right now, it looks like I'll have to turn my own tap (I have access to a lathe at the autoshop.) The reason is finding a tool bit to cut the interior is not a trivial problem given the I.D. is going to be 5/16 inch, 0.3125" (7.9375 mm.) Fortunately, the adapter part will be aluminum so I can make a tap using steel stock; cut the threads; grind gaps for shavings, and; heat treat to harden.
The shaft is hollow but the I.D. is 0.1945" (4.9403 mm) and I need a shaft of 0.250" (6.35 mm.)
Thanks,
Bob Wilson