sharpening milling cutter or drill bits for hollowing

[hughie]

Finally got some reasonable shots of my sharpening efforts on slot drills. They resemble drill bits as they have only two flutes. Basically I sharpen them into a thick spade bit and half round as well. Being HSS and well used they will have some damge to them. So dont worry how pretty they look as to the grinds, as long as they cut.

They make very good low cost hollowing tools.....free Sometimes if your lucky you may pick someold cobalt cutters. These are even better, but darn hard to grind. But then, if they are darn hard to grind they, will be darn hard to wear out. Might need a green grinding wheel though.

Its pretty much the way you can grind Oland type tool bits, half round with a small relief angle.

[Ed Reiss]

...good rework for something that otherwise might be a throw-away

[OGYT]

Thanks for the pics, Hughie. I gotta try something like this. Looks interesting.... again. I can remember (but not the specifics) about another post a while back about this subject.

[hughie]

Al,

Check out some of your local engineering workshops. When these slot drills wear out or get badly damaged they are thrown away. A couple of handfuls would do you for years.
They are really easy to grind up and given the price. Theres no worries if you muck one up, just grind it some more.

[joe greiner]

Neat, hughie. Easy to experiment with different presentations too, and expand the repertoire of how to "fail." (--> succeed.)

Cheers,
Joe