Presser Foot Thumb Screw (Thread Size/ Screw Tap?)

[shoemaker4]

 

Does anybody know the thread size/tap for a Presser Foot Regulating Thumb Screw commonly found on Industrials, say the 31-15?

I have an old junk machine that was basically used as a hole puncher and am drilling/tapping a few holes to make it a complete sewing machine.
typically the screw holes themselves look to be 1/2 in diameter but I’m not having any luck finding the thread size/tap neither Metric nor Imperial.
 

 

 

[kgg]

28 minutes ago, shoemaker4 said:

Does anybody know the thread size/tap for a Presser Foot Regulating Thumb Screw commonly found on Industrials, say the 31-15?

If it is a Singer don't be surprised at not finding a tap as Singer and some Juki's had their own specific custom thread.

kgg

[CowboyBob]

It is a 1/2" x28 tpi.I made a tap once out of an old one (screw)by cutting 4 slots in the bottom up a 1/2" or so & squeezed it in alittle so it would start.

[shoepatcher]

taps are cheap on google.  Found one for $9.95 plus shipping

glenn

[shoemaker4]

Thanks guys.