Aircraft Tool Supply Threaded Drill Bits #40, #30, #21, #12 (4-Pack)

Good quality for the price 👌

I only got these drill bits because I was lucky enough to get a drill that uses these bits at an auction. I just wanted to get a sample set of bits for the day I need to use these bits in tight quarters. I've kept your address in case I need to order other sizes.

The number 40 bit broke on the first hole, but I have to take credit for the assist rather than totally blaming the bit. It is used in a 90 degree drill attachment, and when it drilled through the 1/8" aluminum, instead of maintaining speed and pulling it out, I let the drill slow and didn't hold enough pressure on the 90 degree drill attachment so it twisted and snapped the bit.I've been drilling a large number of holes with a normal number 40 bit and it flexes without breaking, so yes, I feel the bit isn't very strong. It wasn't as sharp as my other bits were either, and took about 10 minutes to drill through 1/8" aluminum.Being more careful with the #30 and #20, I've managed to keep them from twisting and they haven't broken yet.

Worked well on sheet aluminum.

Expected the long version of these bits, as shown in the picture, but received the normal (short) version. This isn't a matter of preference, the tool requires the long version.

These drill bits saved time and effort constructing an RV-4 homebuilt aircraft. Thanks

the order meet my expectations.

Broke all four very easily, might as well be made out of copper very cheap and soft bits. Don't buy.