[David Paule]

I've been examining my #40 drill bits with a 10x magnifying glass, and it seems that there's quite a bit of variation in the accuracy of the grinding of their points. Enough that poorly-ground ones don't start drilling well at all.

This was from several packages of half a dozen each that I've got in a box.

Anyhow, if you want good holes, check those tips with a magnifier!

Dave

 

[David Paule]

I now have some bits from gen-aircraft-hardware.com. These are excellent.

However, since they came after I'd started this thread and I use my real name and location, there is of course a possibility that they might have been selected.

I recommend that you check your bits with a magnifying glass before using. Still, these are pretty nice.

Dave
P.S. A magnifying glass is one of those must-have tools, FYI.

 

[WingsOnWheels]

I have received a few bits in the past (not from Gen-AC) that had the tip cut at the wrong angle. They wouldn't even start a hole in aluminum.