"Gunner Asch" wrote in message
...
On Sun, 05 Jul 2009 20:42:03 +0700, Bruce In Bangkok
wrote:

On Sun, 05 Jul 2009 08:19:06 GMT, "Harold and Susan Vordos"
wrote:


"Calif Bill" wrote in message
newsPydnduUWOzGZdbXnZ2dnUVZ_gWdnZ2d@earthlink .com...
snip---


Impossible to drill an undersize hole. As the drill will not go
through
the hole. Sharpen the end offset as to the center point and you will
get
a bigger hole.

No, it isn't. It's not all that uncommon.

Harold

Errr Harold, will you explain that a tiny bit.

I measure the shank of a, say .500", drill. Stick in the machine and
drill a .450" diameter hole? In mild steel? 1 inch thick?

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Harold is quite right. Ive been sorting out boxes of drill bits..and
the shank diameter is NOT always the same as the bit diameter.

Ive measured Good .500 bits and they tend to actually mic out at
.495-.502

Quite a range..and a head scratcher when the hole is too small.

Gunner

Damn, my posts aren't showing up on my monitor, but the responses to them
are. Bear with me.

As has been alluded, drills can drill a hole that is undersized from the
designated (and measured) diameter of the drill. It happens by the drill
creating a less than round hole, so the minor diameter is smaller in size
than the drill measures at the tip. A like sized pin won't fit the hole.

For those that don't know, drills are not straight. They are ground with a
minor taper towards the shank, which is almost always a few thou smaller in
diameter than the drill tip. That's to insure that the drill doesn't bind
in deep holes, assuming they cut size. They have been known to!

Twist drills are a miserable cutting tool at best-----although they do
create holes! The web of a drill does not cut-----it displaces metal so the
cutting lips can remove it. That's why split point drills do so well. They
actually cut at the web.

Harold