Drill bits

[JoshEarl]

Nathan,

Thanks for the advice--I'll give this a shot, too. When the bit starts to chatter and chip the steel instead of peeling it into nice shavings, I'm getting smoke and little bits of flying steel with smoke contrails following their path.

I tried WD-40, and so far I'm having better luck with the light machine oil.

Sharpening the bits won't be hard--I've done it before with success. But stopping every 10 holes to resharpen the bit isn't really very efficient.

Thanks again,
Josh

Come on folks, don't make this harder than it has to be....

Listen to Nathan The Machinist!

Everybody is telling you use lube and go slow. While there is some truth to this, it can be over done. The most common mistake I see with inexperienced people is not feeding hard enough, and just letting the bit rub. That's bad.

Use WD40 (only thing its good for IMO), oil, water, lard, soap, whatever, you're trying to keep the cutter cool! The lube just isn't that important (not so with a tap though!) The purpose of pecking is to break the chip and let coolant down into the hole.

500 RPM isn't too fast for a 1/8" drill. I'd probably drill that, in 1095, at about 1000 RPM and 3 inches per minute feed rate with a water based coolant. You spin faster with small bits, slower with big. If you're getting chatter, you're feeding too slow or running to fast. You want your periphery cutter speed around 40 surface feet per minute. Do the math. 150 is bad (in tool steel), 20 is pointlessly slow.

The last thing you want to do on a carbide laced steel is pause on the hard bits and let it eat up your cutter. Lean into that thing!

Wear safety glasses. When you're machining right, you're really not that far away from breaking something!

 

[fitzo]

....i think its ridiculous to throw away a dull bit, when about 15 seconds at the grinder will have it sharper than new after a little practice. would you throw away a knife the first time it got dull? i should hope we can all look at the edge geometry on a drill bit and put a new, sharp edge on it. thats what we make, sharp things!
-Lou

You can do your things your way and I'll do mine the way I wish. I throw away small bits or use 'em for something else, my choice, and I've been doing it that way longer than you've been alive. I haven't come in and said some of the ways I've seen you doing things is ridiculous. Accord me the same kindness.