Drilling brass?

[Ray Dunakin]

I'm in the middle of drilling a bunch of #80 holes through some flattened brass tubes. The first four holes went pretty quickly but now it's taking forever. Is this normal -- should I expect to replace the bits after just a few holes? Or do I need better drill bits? What kind should I look for? Is there some other trick to this?

[Bexley]

1. Are you using some sort of cutting fluid? If not, you should. Any kind of light oil will do.

2. The second thing I'd check is the speed of the bit. Which, were I more prepared, I'd calculate for you. Except my Machinery's Handbook is at school.

(Scratch that- thanks to the Intarwebs, you should be using a speed of about 80,000 to 100,000 rpm. Or, as fast as you can go, since that's probably a lot faster than any tool you might have.)

If you are drilling them by hand with a pin vise, then only #1 would apply.

[Ray Dunakin]

Yeah, I'm doing it by hand with a pin vise, guess I forgot to mention that.

[Scratchman]

Ray, I use flattened tubing a lot, but I will use the aluminum instead of the brass. The aluminum is much easier to drill.

Gordon Birrell

http://www.flickr.com/photos/77318580@N00/

 

[lab-dad]

Carbide bits, just dont force them.

-Marty

[JohnP]

You probably know brass comes in different hardness so the softer brass may be better for this application. Also, check the tip. Sometimes brass will gall on the cutting edge and stick there. Using a light oil will help. If you don't want oil all over isopropyl alcohol is OK.

And try twisting your fingers at 100,000 rpm. That'll do.

John

[lab-dad]

Heating the brass to a dull red and letting it cool will also soften it........I think................

[RoughboyModelworks]

Is there a particular reason you're trying to do this by hand Ray? It will be much easier and faster if you can power the drill bit with something other than your fingers. Breakage is caused because, no matter how steady your hand, it's nearly impossible to maintain the correct cutting angle between the bit and the brass tube and a consistent speed when turning by hand. I assume you're starting with a small indent in the brass surface to prevent the bit from wandering... small dimple from a carbide scriber would be enough to locate the center.

Paul