I have one drill bit that looks like its intended specifically to go in a
collet. Its got a 3/8 shank about 5/8" long and then about a jobber length
1/4 drill bit. It is very precise. It was in a box of misc end mills I
bought at a yard sale. When I stick it in a 3/8 collet I get no wobble at
all. Its as good or better than putting a 1/4 bit in a 1/4 collet, and way
better than sticking my mandrel mounted drill chuck in a collet to hold a
drill bit. I seem to recall somebody mentioned these bits designed to be
used in a mill like this.

What are they called?

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Bob La Londe wrote:
I have one drill bit that looks like its intended specifically to go in
a collet. Its got a 3/8 shank about 5/8" long and then about a jobber
length 1/4 drill bit. It is very precise. It was in a box of misc end
mills I bought at a yard sale. When I stick it in a 3/8 collet I get no
wobble at all. Its as good or better than putting a 1/4 bit in a 1/4
collet, and way better than sticking my mandrel mounted drill chuck in a
collet to hold a drill bit. I seem to recall somebody mentioned these
bits designed to be used in a mill like this.

What are they called?

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Home made drill bit adapters. I have quite a few in my tool box.
One that gets a lot of use is the #7 (tap drill for 1/4-20)
and similar ones for smaller size screws.
...lew...

What's that Lassie? You say that Bob La Londe fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Wed, 10 Feb 2010 08:17:39 -0700:

I have one drill bit that looks like its intended specifically to go in a
collet. Its got a 3/8 shank about 5/8" long and then about a jobber length
1/4 drill bit. It is very precise. It was in a box of misc end mills I
bought at a yard sale. When I stick it in a 3/8 collet I get no wobble at
all. Its as good or better than putting a 1/4 bit in a 1/4 collet, and way
better than sticking my mandrel mounted drill chuck in a collet to hold a
drill bit. I seem to recall somebody mentioned these bits designed to be
used in a mill like this.

What are they called?

Does the shank have a flat milled on it?

--

Dan H.
northshore MA.

"dan" wrote in message
...
What's that Lassie? You say that Bob La Londe fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Wed, 10 Feb 2010 08:17:39 -0700:

I have one drill bit that looks like its intended specifically to go in a
collet. Its got a 3/8 shank about 5/8" long and then about a jobber
length
1/4 drill bit. It is very precise. It was in a box of misc end mills I
bought at a yard sale. When I stick it in a 3/8 collet I get no wobble at
all. Its as good or better than putting a 1/4 bit in a 1/4 collet, and
way
better than sticking my mandrel mounted drill chuck in a collet to hold a
drill bit. I seem to recall somebody mentioned these bits designed to be
used in a mill like this.

What are they called?

Does the shank have a flat milled on it?

No.

On Feb 10, 10:17*am, "Bob La Londe" wrote:
I have one drill bit that looks like its intended specifically to go in a
collet. *Its got a 3/8 shank about 5/8" long and then about a jobber length
1/4 drill bit. *It is very precise. *It was in a box of misc end mills I
bought at a yard sale. *When I stick it in a 3/8 collet I get no wobble at
all. *Its as good or better than putting a 1/4 bit in a 1/4 collet, and way
better than sticking my mandrel mounted drill chuck in a collet to hold a
drill bit. * I seem to recall somebody mentioned these bits designed to be
used in a mill like this.

What are they called?


Probably some some sort of CNC-qualified drill or something, possibly
for a dedicated drilling machine that only takes bits with a certain
shank size. Is it coolant through?

"woodworker88" wrote in message
...
On Feb 10, 10:17 am, "Bob La Londe" wrote:
I have one drill bit that looks like its intended specifically to go in a
collet. Its got a 3/8 shank about 5/8" long and then about a jobber
length
1/4 drill bit. It is very precise. It was in a box of misc end mills I
bought at a yard sale. When I stick it in a 3/8 collet I get no wobble at
all. Its as good or better than putting a 1/4 bit in a 1/4 collet, and
way
better than sticking my mandrel mounted drill chuck in a collet to hold a
drill bit. I seem to recall somebody mentioned these bits designed to be
used in a mill like this.

What are they called?


Probably some some sort of CNC-qualified drill or something, possibly
for a dedicated drilling machine that only takes bits with a certain
shank size. Is it coolant through?

No, it does not have coolant ports in the bit. its just a drill bit except
for that big old club on the end.

Bob La Londe wrote:
I have one drill bit that looks like its intended specifically to go in
a collet. Its got a 3/8 shank about 5/8" long and then about a jobber
length 1/4 drill bit. It is very precise. It was in a box of misc end
mills I bought at a yard sale. When I stick it in a 3/8 collet I get no
wobble at all. Its as good or better than putting a 1/4 bit in a 1/4
collet, and way better than sticking my mandrel mounted drill chuck in a
collet to hold a drill bit. I seem to recall somebody mentioned these
bits designed to be used in a mill like this.

What are they called?

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They are sometimes called printed circuit drills in the smaller sizes.

http://www1.mscdirect.com/CGI/GSDRVS...IT4NO=79713667

John