On a video I was watching on youtube, the guy made a comment that he had ground flats on his drill bit specifically for drilling brass. When he used it the swarf was small flake like chips. Anyone have any information on grinding these flats on the drill bit for brass?
Thanks,
Ed
There was a post on HMEM about it a while back. You simply grind off the front edge of the cutting edge square, if I remember correctly. The thread was pretty specific and included pics as I recall.
Ed,
All you do is dull the cutting edge a bit to keep the drill from screwing into the stock. Just lightly touch the cutting edge of the drill on the wheel at 45ยบ (it doesn't take much) and life will be good. BTW, they work for drilling plastic as well.
Tom
I do the same as Tom - only I use a stone, just find it a little easier to control.
it does stop the drill from "digging" in and the "break out" is usually more controlled and gentler.
Basically reduces the snatching.
DaveH
Thanks for all of the info. I'll have to give it a try and see how it goes.
Ed
Drill bits for brass need zero rake, just like a lathe tool for brass is zero rake. Most easily done by grinding the cutting edges of the bit (lightly)to be perpendicular to the work--- that is, grind a flat that's at a right angle to the surface. It doesn't take much, just need to get the sharp, angular edge of the bit blunted to zero rake.
I bought a set of Enco bits on sale just for this, since I was going to modify them, they seem to answer every purpose....
I did this using my surface grinder, but a bench grinder would do. My bits cut clean and don't hog-in; also have used them on plastics.
I was going to suggest also, to buy a set of bits and grind them just for brass, if you use brass often.
Don't need a whole set, but buy whatever sizes you feel you use.
(09-14-2012, 06:18 PM)sasquatch Wrote: [ -> ]I was going to suggest also, to buy a set of bits and grind them just for brass, if you use brass often.
Don't need a whole set, but buy whatever sizes you feel you use.
That's my plan. I'll buy them and grind them as I need them.
Ed