- Joined
- Oct 4, 2014
- Messages
- 172
last week while shopping at a local surplus center I ran across a drill bit I haven't seen before. The way the tip was ground is what got my attention . There were several of them in a small bin marked at 50 cents each so I bought a couple for the heck of it. They are 17/64" X 2-1/2" with kind of an inverted grind on the cutting edge.
I drilled about halfway through a piece of 1/2" aluminum to see how it cut and it leaves an almost flat bottomed hole, just a little nib in the center sticking up. Then I drilled a through hole and it was nice and clean when it came through. I did use some WD-40 as a lubricant.
Anybody seen these before or no what there purpose is ? There also was another bin with some stubby 17/64" 135* split points of which I bought several.
I drilled about halfway through a piece of 1/2" aluminum to see how it cut and it leaves an almost flat bottomed hole, just a little nib in the center sticking up. Then I drilled a through hole and it was nice and clean when it came through. I did use some WD-40 as a lubricant.
Anybody seen these before or no what there purpose is ? There also was another bin with some stubby 17/64" 135* split points of which I bought several.