Roger Shoaf wrote:
"mcp6453" wrote in message
...
Can someone give me a quick primer on drill bits? All I think I know is
that
high speed steel is the worst. Carbide tips are good. Where do cobalt and
black
oxide fit into the mix? My interest in is "standard" drill bits for thin
metals
and wood rather than masonry.

My Craftsmen sets are showing their age and wear. Where is a good place to
buy
drill bits? Should I look at an industrial supplier rather than a
retailer?

No, high speed steel is just fine in appropriate materials like mild steel,
or softer materials.

Carbide is nice if you are working on hard material or if you are in a
production environment where you have a need for higher speed and longer
tool life.

Carbide tip drills are usually used for masonry or in some cases to drill
holes in hard materials.

Cobalt is used for steels that are a little bit harder than HSS can handle
(retainer pins) but not glass hard things like files.

Black oxide or the gold colored titanium nitride bits give you some
advantages in corrosion protection and help resist galling, bit in and of
itself means a whole lot less than the quality and the geometry of the steel
below.

Check out McMaster Carr or another machine shop supply for the better
quality drill bits, and you might want to order a few extra of the more
commonly used sizes.


Excellent information, Roger. Regarding masonry bits, some packages say they are
usable in hammer drills, some are not. Is there a way to look at a bit and tell
whether it is rated for use in a hammer drill? While cleaning up my shop
yesterday, I found a brand new, in-the-box, hammer drill that I received as a
Christmas present a few years ago. Go figure.