what size drill for tap?

[Teyber12]

hello!

On my x3, i swapped the gears, but one of the pulleys was not supported as you can see here

On the left, is the motor shaft. The gear popped up when i was machining a part and destroyed the belt, so i need to hold the gear down.

I was going to drill a hole in the shaft and tap it to 10-32 so i can use a little 10-32 screw that would be perfect i have laying around.

I cannot find what is the proper size drill bit however, that i need to use to drill a proper hole so i can tap it proper. i only have one shot to do this correctly.

Thanks a million

[Geof]

#21 drill is for 10-32 and I think 5/32" is very close. Depending on how deep the hole is and how much thread engagement is possible you can go to 11/32"; this is easier to tap but the thread depth is reduced to about 60% of full form whereas #21 gives you about 75%.