How to mark and drill?

[Tom Bender]

I need to drill a hole in the center of the edge of a board about 1/2" thick. Looking for a shop made solution. The challenges:

Measuring and marking within a few thou'

Hard spots in the grain push the center punch off the mark - It's oak

Hard spots push the drill bit off the punch mark

Drill press tends to flex just enough to throw off a clamped setup, especially with a wide board

Not so easy to clamp a drilling guide to the workpiece

[Cameron Wood]

Drill a hole in a guide block, & clamp to the workpiece.

[andy bessette]

Self-centering doweling jigs are made just for this. I've had mine for many decades.

[Jim Koepke]

I need to drill a hole in the center of the edge of a board about 1/2" thick. Looking for a shop made solution. The challenges:

Measuring and marking within a few thou'

Hard spots in the grain push the center punch off the mark - It's oak

Hard spots push the drill bit off the punch mark

Drill press tends to flex just enough to throw off a clamped setup, especially with a wide board

Not so easy to clamp a drilling guide to the workpiece

Answering a few questions might be helpful.

1) How big of a hole?

2) Why "within a few thuo'?"

For me one of the hardest places to mark is on the end grain of hardwood blanks going to the lathe.

I start with a very sharp (shop made) scratch awl.

Scratch Awl and Burnisher with Acorns.jpg

This one has four facets. A three faceted awl would likely work just as well. This was made from a piece of HSS drill stock. With the tip and sides sharp it can actually do a little drilling. The wedging action can be used to push wood sideways if your hole is slightly off.

After the mark looks good the hole can be made a little larger with a gimlet.

Various Gimlets.jpg

The smallest one in the box is about 3/32".

If you have an auger bit, the lead screw on that may be able to start the bore to make a nice start for a twist drill bit.

jtk

[Jimmy Harris]

It depends on the size of the hole, but if you can use one, a Forstner or brad point bit does a pretty good job of not wandering in the wood with a drill press. Auger bits also work well for this.

[Tom Bender]

Thanks for the suggestions. I'm making a jig using a machinist's centering drill. This has a short fat shank and a small point so it won't deflect. I'll run it thru a guide made from some hard maple. Once it establishes the hole it should be ok. The guide will have centering screws which will need to be adjusted. Feeling optimistic.