nikbrown

Drilling bench holes?

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So I need to drill a bunch of 3/4" dog holes in my bench. I suck at keeping my handheld drill square so I was thinking about drilling my holes on the drill press before I glued up that strip to the bench. I'll be drilling 6" through a 12/4 piece of ash.

What kind of bit would you use? forstner? spade? Brad-point?

I would think the best one would be a Forstner bit... but can I find a 3/4" Forstner bit that is at least 7" long?

I guess I could start it with a Forstner and then switch to something else once I run out of depth.

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I set mine at the back fence and shot it with 30-06 hollow point just to see if it would work. Result was a hole too small on the top and 5 inches wide at the back. Bad idea, back to square one. Perhaps I should try the 300 Winchester Mag??

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I guess I could start it with a Forstner and then switch to something else once I run out of depth.

My bench top is 4" thick ash. I used a drill press with a 3/4" forstner and drilled all the holes in the dog strip approximately 2" deep. I then used a brace and bit with 12" throw to finish drilling the rest of the way through. It wasn't that hard, and with the holes started plumb, getting off kilter with the brace was not a problem.

Just make sure you mark the depth of the hole on the brace so you only drill until the lead screw pokes through, then go back and finish from the other side to avoid some major blowout.

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Lee valley sells 3/4" spiral upcut bits. Drop one in a plunge router and you get a perfectly plum 3/4" hole. If it's still not deep enough, you can then use a 3/4" drill bit (I'd use a auger bit) to complete going through the bench.

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Hey Nik,

I've thought about this too because my workbench has square dog holes and I need a nice round hole for a holdfast. So here's what I thought I would try. I haven't tried this yet, but it's an idea.

  1. Create a guide block by drilling a hole the exact size as the shaft of your forstner bit through a nice hard block on the drill press
  2. On the underside of the block, drill a recess for the cutting head of your forstner bit
  3. Feed the bit through the block, and chuck it in the drill
  4. Clamp the block in place and drill the hole
  5. Extend the hole with a bit extender like this one http://www.eagleamerica.com/product/v301-0107/woodboring_-_forstner_bits

Other ideas I've seen mentioned are similar, although they start the hole with the forstner bit and alignment block, and finish with a spade bit (sometimes in an alignment block, sometimes not).

I hope this helps.

Matt Gradwohl (Upper Cut)

Upper Cut Woodworks

http://uppercutwoodworks.com/

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Nik,

I'd go the auger bit route. Make a guide at the drill press the hog your holes. If you're worried about the tear out on the underside, wrap some tape on the bit and stop just before the shaft breaks through. The pilot portion will have already gone through..drill up and use a small flush trim bit on a small router to clean it up. Personally...I'd just plow on through, considering the top should be plenty thick and you're never gonna crawl under to see the tear out.

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Nik,

One thing you might test out on at least one hole if you plan to use holdfasts in your dog holes, check to see if the holdfast holds well in the thickness of your top. I have problems with holdfasts in my bench because the holes are exactly 3/4" and with the thickness of the bench it sometimes has a hard time holding. (I've tried the sanding the holdfast shaft, it still only holds about 50% of the time)

Many people have suggested counterboring a short distance on the bottom side of the hole with a 1" forstner. It would be easier to do this initially than after you have already drilled the 3/4" holes.

I haven't gotten around to it yet, but I plan on going back and attempting to counterbore my already drilled holes (not looking forward to that). At least I didn't glue my benchtop onto the base, so I can take the top off of the base for this operation.

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Thanks guys! I got a new Forstner bit (old one was dull) and an auger bit. I like the idea of counter boring the bottom for better holdfast usage.

Also nice tip on the guide block! Much better than trying to balance that big beam on the drill press.

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I like Dyami's idea the best; perfect hole that you'll use as a guide hole for the auger bit (powered or hand). Certainly would be easier to plow out a whole row running the router on an edge guide.

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It has been said above, but I build my top out of Ash and started with a forstner at the press then switched to brace and bit to finish it off. The guide hole created at the press makes it idiot proof.

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I used a forstner bit in a hand drill with a circular bubble level on the back. The table was leveled first so it worked out fine. When that bottomed out I switched to a spade bit.

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I drilled mine with a corded hand held drill with an auger bit and this: drill guide.

I also clamped a backer board of plywood to prevent blowout on the under side. It went easier than I expected.

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Got around to drilling my first dog holes this morning.

Went full depth (about 2.5") with a 3/4" Forstner bit from the top and full depth with a 7/8" Forstner bit form the bottom. Then connected them with a 3/4" auger bit.

post-1793-0-03724700-1290087592_thumb.jp

Yay! Tail vice finished. Now I just need to put the rest of the apron on so I have something to clamp to.

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Is that one of the new Veritas Quick-Release Sliding Tail Vises?

You dog! I have one on my Christmas list.

I would be interested to know how you like it, once you get the edge of the bench assembled.

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Looks nice, I actually do mine like was stated above with the router but I just use a template and guide bushing finished off with a forstner bit so that I have a perfect plum hole to start with. Just goes to show that there are many different ways to skin a cat.

Nate

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