Good, bad, and ugly - odd tools

[J Tiers]

Many wood cutting tools are easily sharpened with a file, clearly not very hard. Some obviously are not for metal, others less obviously. An auger bit is pretty obvious, but twist drills, not so much.

[huntinguy]

Non clearanced twist drills for wood are not unheard of. Not so common now though.

[sch]

Heard a presentation by an Iscar rep 7-8 yrs ago, he said that industrial milling bits/drills with lube-coolant holes down the flutes were made by cutting the flutes and holes straight then
twisting the bit into a helix before hardening and finish grinding. Don't see any other way to make a hole down a spiral flute for coolant injection.

[Forestgnome]

Here is an ugly drill bit.



It came out of a pack of #10 jobbers bits. Does anyone know how drill bits are made?

Stu

I have one just like that. I thought is was a reversible bit.

[Daveb]

I put a drill bit in the chuck and thought it wasn't cutting very well, when I looked at it, it was a left hand drill, it cut OK when I reversed the drill. I discovered the drill was a standard part, they used to be (maybe still are) used in capstan lathes. I've also had the drills which straighten out rather than drill a hole, I think they're still available but you may have to search for them.