Boring holdfast holes

[overland]

My bench is a 6" thick oak slab. Can I drill a couple holdfast holes with a spade bit or a hand brace and still get it straight? That's what I've got at hand.

[Aram]

My bench is a 6" thick oak slab. Can I drill a couple holdfast holes with a spade bit or a hand brace and still get it straight? That's what I've got at hand.

I have not tried it myself, but Lie-Nielsen recommends this:

" 3/4" (We recommend Wood Owl Auger Bits for drilling holes)"

[Mark A Smith]

I have not tried it myself, but Lie-Nielsen recommends this:

" 3/4" (We recommend Wood Owl Auger Bits for drilling holes)"

I have a 4 inch hard maple bench. Drilled mine using an 18 volt impact driver and a 3/4 inch single flute spiral bit from Home Depot (Ridgid brand). Has a screw lead and 1/4 inch shaft to use in quick-release drills. I could not believe how quickly it pulled itself through my bench. It was really hot by the time it got through. Clips were packed tight and I had to release the bit and psch the shank on through then clean out the clips manually, but it worked.

You can only get 5 inches of depth with this bit, so for 6 inches you'd need a bit extender.

Don't use a spade bit. Use an auger bit of some sort with a lead screw.

[Brent V.]

My bench is a 6" thick oak slab. Can I drill a couple holdfast holes with a spade bit or a hand brace and still get it straight? That's what I've got at hand.

I have not had good luck with spade bits. They leave a rough hole, and are better for quick low-quality holes in construction wood.

I drilled the dog holes in my workbench (with a 6-inch Douglas Fir top) using a long 3/4" brad-point twist drill and the aid of two small squares for sighting. I was able to drill straight. I think you could do the same with a hand brace and auger bit.

[Derek Cohen]

My bench is a 6" thick oak slab. Can I drill a couple holdfast holes with a spade bit or a hand brace and still get it straight? That's what I've got at hand.

I purchased some Owl bits since drilling my bench. They are excellent bits.

I used a sharp Jennings ...





Remember that you will need to bore vertically. This means that you will benefit from strategically placed squares to sight against.

My bench is 3 1/2" thick, and my holdfasts work very well. I believe that for benches close to 4" and thicker, you will need to bore them wider from the underside to effectively reduce thickness.

Regards from Perth

Derek

[5thumbs]

I purchased some Owl bits since drilling my bench. They are excellent bits.

I used a sharp Jennings ...





Remember that you will need to bore vertically. This means that you will benefit from strategically placed squares to sight against.

My bench is 3 1/2" thick, and my holdfasts work very well. I believe that for benches close to 4" and thicker, you will need to bore them wider from the underside to effectively reduce thickness.

Regards from Perth

Derek

Excellent Point about the 4" and thicker benches. I found that using a  round rasp on the underside worked quite well - however, do so gently. It's easy to remove material to make the hole wider, putting it back is another matter.

[Derek Cohen]

I would drill a 1/16" pilot hole all the way through. You may get away with a 1/8" - it all depends on the width of the leading screw of the bit. The hole must be smaller than the screw so that the screw can still bite into the pilot hole.

From the underside of the bench, use a wider-than-3/4" bit to drill up 2". Then from the top of the bench, you can drill down 4" with a 3/4" bit.

The advantage of the pilot hole is that it will make it easier to drill through hard woods. You can use less down force with the brace.

Regards from Perth

Derek

[Philip1231]

I used a plunge router with this bit: got me about half way through a 4" top.  I used a spade bit for the balance.

[Bibliophile 13]

You can always use both! Start with the auger bit, so you get a nice, clean entrance hole. When your arms give out, you can switch to the spade bit. If you can stop just as the spur comes through the bottom, you can even finish with the brace from underneath for a nice, clean exit hole. If you have a brace with a 12" throw or more, you might find it just as easy to bore the whole hole by hand. If you only have a smaller, 10" throw, however, then you'll probably want to do this mostly with the spade bit.

Derek suggests drilling a small pilot hole first. Not a bad idea for a hard wood like the oak. Only problem I see is that you probably don't have a 6" long 1/16" bit lying around your shop.

As to drilling straight, don't worry too much about it. Holdfasts hold the same in slightly crooked holes as they do in dead-straight holes. Nevertheless, you can bore a pretty darn straight hole with a brace. As you begin, use a square to check that you're holding the brace straight. Move the square around the hole a couple times as you make your first few turns and the lips begin to bite. Then, once you've gone in an inch or so, the brace will pretty much follow itself straight through the hole. Auger bits don't usually wander like regular spiral bits do in a power drill.

[Kiefer]

I used a 3/4 inch forstner bit in a drill press to make a vertical hole in a 2x4.  I then used this as a guide for using a Woodowl overdrive bit chucked in a hand held drill.  Drilling all the holes in my bench took about 20 minutes.