Joe AutoDrill wrote:

"steamer" wrote in message
...

--Well at least some of them are tap drills for various threads;
from memory: F = 5/16-18, G = 1/8" pipe (?), #21 = 10-32, etc. And then
there's the problem of over and undersize threads for various
applications;
i.e. sometimes you'll want to use a drill that's a few thou over if you're
tapping a hole that's going to be anodized. I suspect that number and
letter
drills 'evolved' to fill these sort of gaps.


That makes sense for some sizes... But it makes you wonder why the metric
system or even a fully decimal system doesn't take off...

Imagine simply saying that drills are available every thousanth up to a
certain size and then every 2 thousanths up to some larger size, so on and
so forth, etc.

I can see a supplier offering drills in .001" increments up to 1" and having
a market *IF* they became well known.

Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R






1000 drill sizes on the shelf? I have ground down drills a couple of
thou once in a while when I didn't have the exact size I needed and I
had to finish the job.


John