I recently ordered some 0-80 screws and a corresponding tap but I can't find a convertion table that tells me what size drill bit to use. Anyone know?

Gary Mulkey

Gary,

According to my chart you need a 3/64 drill bit. This is based on 75% full thread.

This is from the Texas Knifemakers Supply chart I picked up at the Spirit of Steel Show.

Thanks, Bob.

Gary

MSC has a real nice conversion table in the back of thier catalog, or they will send you one.
Every shop needs a drill and tap table handy.

For titanium I have been using a # 55 for 0 80 taps. Screws are tight and hold good. Haven't stripped any yet. So if you experience lots of tap breakage you might try that.

Regards

Thanks,

I appreciate the info.

Gary

My chart calls for a 3/64 (.047") tap drill, and for titanium that's what I use. I also use taper taps instead of plug taps, which cut a little better (McMaster-Carr has them - most knife supply houses only have plug taps).

I mostly use 1-72 as I like the extra strength over 0-80, but I use 0-80 to hold the thumb stud on. As the hole in the thumb stud is deeper that on a liner, I found that a number 55 drill (.052") broke fewer taps.

Holes with both tap drills hold well and don't strip.