Here is a simple problem that I would like an answer to.

I have drilled a 3/8" hole exactly where I want it only it should have been
1/2". How do I overbore it to 1/2" without changing its exact position.
Needless to say it cannot be done on a drillpress and the material is
wood......

One possibility:
Mark the center of a 3/8" dowel, insert dowel into existing hole, drill new
hole. A forstner bit might work best, depending on the original material.

Another possibility:
Make a drill guide jig on a drill press with a through hole 3/8" dia. and a
concentric 1/2" dia. hole drilled halfway through (like a deep counterbore) a
scrap piece of wood. Use the small hole and bit to locate the jig, then clamp it
to your workpiece. Then use the large hole to guide the 1/2" bit.
--
JeffB
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mike hide wrote:
Here is a simple problem that I would like an answer to.

I have drilled a 3/8" hole exactly where I want it only it should have been
1/2". How do I overbore it to 1/2" without changing its exact position.
Needless to say it cannot be done on a drillpress and the material is
wood......

JeffB writes:

One possibility:
Mark the center of a 3/8" dowel, insert dowel into existing hole,
drill new hole. A forstner bit might work best, depending on the
original material.

I'd glue the dowel into the hole, let it dry, and then bore it out.
Good idea to mark th center first.

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Sending unsolicited commercial e-mail to this account incurs a fee of
$500 per message, and acknowledges the legality of this contract.

First: install a 3/8 drill in the drillpress. Do not start the motor.......
Second: lower the drill into the existing hole and carefully clamp the wood
to the drill base. You now have the exact center of the existing hole.
Third: replace the 3/8 bit with the 1/2" bit.

John

You could also buy a stepped drill bit. Insert it up to the 3/8"
portion to line it up, then drill out to the 1/2" diameter.

"mike hide" wrote in message
...
Here is a simple problem that I would like an answer to.

I have drilled a 3/8" hole exactly where I want it only it should have
been 1/2". How do I overbore it to 1/2" without changing its exact
position. Needless to say it cannot be done on a drillpress and the
material is wood......

Regular twist bits are self centering. Experiment with using a regular 1/2"
bit and see if the results are acceptable.

Or use the method for drilling larger holes for door lock and handle sets.
Drill a hole with a 1/2" forstner bit through a 1x4 then center and clamp
the 1x4 over the 3/8" hole. Then use the clamped 1x4 and its hold to guide
the 1/2" bit.

"John Eppley" wrote in message
...
First: install a 3/8 drill in the drillpress. Do not start the
motor.......
Second: lower the drill into the existing hole and carefully clamp the
wood to the drill base. You now have the exact center of the existing
hole.
Third: replace the 3/8 bit with the 1/2" bit.

John


appreciate the post John, possibly you did not read my original post, I
cannot use the drill press only indirectly.

"mike hide" wrote in message
...
Here is a simple problem that I would like an answer to.

I have drilled a 3/8" hole exactly where I want it only it should have
been 1/2". How do I overbore it to 1/2" without changing its exact
position. Needless to say it cannot be done on a drillpress and the
material is wood......

Define precision? 1/32", .001", etc...

Someone else said to use a step drill - if you have one and depth doesn't
matter or it is a through hole, that might be the best answer. Insert the
3/8" portion and then turn the power on and drill out the 1/2" diameter...
--


Regards,
Joe Agro, Jr.
(800) 871-5022
(908) 542-0244
Automatic / Pneumatic Drills: http://www.AutoDrill.com
Multiple Spindle Drills: http://www.Multi-Drill.com

V8013-R

"mike hide" wrote in message
...
Here is a simple problem that I would like an answer to.

I have drilled a 3/8" hole exactly where I want it only it should have
been 1/2". How do I overbore it to 1/2" without changing its exact
position. Needless to say it cannot be done on a drillpress and the
material is wood......

Take a 3/8 dowel and mark the exact center. If you don't feel you can do
this accuratly enough, turn one on a lathe and the center will already be
there for you. Cut to length, glue in hole, drill out with 1/2 inch when
dry.

Frank

"mike hide" wrote in message
...
Here is a simple problem that I would like an answer to.

I have drilled a 3/8" hole exactly where I want it only it should have
been 1/2". How do I overbore it to 1/2" without changing its exact
position. Needless to say it cannot be done on a drillpress and the
material is wood......


Percision boring?

I had a 12th grade Physics instructor that could probably help you out.

Locutus wrote:

Percision boring?

I had a 12th grade Physics instructor that could probably help you out.



For some reason, I can still crack up my wife when I show here a "boring
machine" in a catalog, and talk about more exciting things to buy.