Pilot hole size (tap drill size) for 10-32 thread?

Question

I need to drill some fine threads in metal. It's a 10-32 screw size and my chart tells me that I need a #21 drill bit. I don't have this. The imperial drill bit I have that's slightly smaller than that hole is a 5/32. Can I use this sized pilot hole if I'm going to hand tap a 10-32 thread. It will be harder for sure because the tap will cut more metal, but has anyone else done this?

Answer 1

Go up 1/64 on the drill size.....................11/64

Drill in a scrap metal, similar to the job item.

Tap the hole, insert a bolt and check for an adequate hold.

If you're satisfied, do the real job.



Plan B ; when you use the 5/32 bit, wriggle it around to slightly oversize the hole.



Plan C ; Buy a #21 drill bit.

Answer 2

Pilot Hole For 10 Screw

Answer 3

if you use your hols for position - you can use any drill size ( but be careful - it must be smaller that other holes, and don't forget drill it to needed size)