Drilling deep hole with Forstner bit

[JohnnyNoName]

I am drilling 3/4" dog holes in my workbench top. The top is 4" thick and my forstner bit won't go all the way through. I used my drill press and forstner bit as The Schwarz recommends, but I'm not sure how to finish up the last 1 1/2". I looked for a longer forstner bit, but I can't locate one. I bought an extension that was just crap (it won't grab the shank straight). I thought that I if at least got most of the hole bored out out, it could serve as a guide for a twist bit or a spade bit if I can't find another solution.

Any thoughts or suggestions?

Jonathan

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[mlehikoinen]

I've been considering the same question, and my thought is, if you have the holes done as deep as you can get them, switch over to an auger bit like this one

Another option would be to pilot the centre with a thin bit and come back through the other side with your forstner bit. I like the first option better though. Ensures alignment right through

[PurpLev]

After you have the top side drilled out (half way through). drill through the centers with a thin bit to transfer the center line to the bottom. flip the boards top to bottom, and drill the bottom half of the holes with your forstner bit. you could even drill a larger hole as the top 2.5" should be more than enough to hold the bench dogs in - but that's up to you really. Another good thing here is that you won't have tear outs on the bottom side of the wholes like you would if you drilled all the way through from the top

[AMarshall]

How about a different method for drilling from the other side? Get a wide board - big enough to cover the drill press table. Clamp this securely to the drill press and lock that table down tight so it won't rotate or shift. Drill a 3/4 hole in the board, and stick in a 3/4" dowel so that it sticks up an inch from the face of the board. Now just flip over the benchtop and slide it around until the dowel seats into one of the holes. Drill the other hole from the bottom of the bench and it will meet the other side perfectly as long as the table doesn't move around.

[wilburpan]

This is the wrong forum for this approach, but for the holdfast holes in my workbench I used a 3/4" auger bit and a brace. I have a brace with a large sweep, and for those of you who have never used one, it's very surprising how much torque you can generate with one. I used my drill press to drill a 3/4" hole in a scrap of 2x4 to act as a guide. And for those who think that hand tools are dog slow, it took me just about 45 seconds to put a 3/4" hole through my 3-1/4" thick benchtop.

[Ben H]

I've not drilled into a top yet...But I've made a couple dozen pepper mills and used an extension on a forstner bit with no problems at all...now years ago I bought an extension from Woodcraft. It was about 10" long and complete junk, the small set screws stripped out after one use.

I did get a small extension, about 4 inches long that works great though.

Perhaps you're being to aggressive with you drill press and extension. Or maybe it's a dull bit. I can't image how drilling through a 3" top can be worse than hollowing out a 10" pepper mill.

[JohnnyNoName]

How about a different method for drilling from the other side? Get a wide board - big enough to cover the drill press table. Clamp this securely to the drill press and lock that table down tight so it won't rotate or shift. Drill a 3/4 hole in the board, and stick in a 3/4" dowel so that it sticks up an inch from the face of the board. Now just flip over the benchtop and slide it around until the dowel seats into one of the holes. Drill the other hole from the bottom of the bench and it will meet the other side perfectly as long as the table doesn't move around.

Aaron -

That's an interesting idea. I might give it a shot.

[JohnnyNoName]

This is the wrong forum for this approach, but for the holdfast holes in my workbench I used a 3/4" auger bit and a brace. I have a brace with a large sweep, and for those of you who have never used one, it's very surprising how much torque you can generate with one. I used my drill press to drill a 3/4" hole in a scrap of 2x4 to act as a guide. And for those who think that hand tools are dog slow, it took me just about 45 seconds to put a 3/4" hole through my 3-1/4" thick benchtop.

Wilbur -

I would like to gives this one a go (trying to improve my hand tool skills) Any suggestions as to buying a bit and brace? Something new. I'm not into the hunting and pecking on Ebay/Craigslist :-)

Jonathan

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[JohnnyNoName]

I've not drilled into a top yet...But I've made a couple dozen pepper mills and used an extension on a forstner bit with no problems at all...now years ago I bought an extension from Woodcraft. It was about 10" long and complete junk, the small set screws stripped out after one use.

I did get a small extension, about 4 inches long that works great though.

Perhaps you're being to aggressive with you drill press and extension. Or maybe it's a dull bit. I can't image how drilling through a 3" top can be worse than hollowing out a 10" pepper mill.

Ben -

It wasn't difficult to drill the holes, I just couldn't reach through. I bought an extension, but it wouldn't hold the bit straight. It just wobbled in the drill press. I guess it was made for drill through studs with a spade bit.

Jonathan

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[Ben H]

Ben -

It wasn't difficult to drill the holes, I just couldn't reach through. I bought an extension, but it wouldn't hold the bit straight. It just wobbled in the drill press. I guess it was made for drill through studs with a spade bit.

Jonathan

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Jonathan, what kind of extension were you using? When I made my previous comment I failed to say that I use a smaller (5 inch or so) when drilling out the pepper mills. Here is what I use It doesn't wobble b/c it's so short. And a spade bit won't fit, the shank is too small. It's made for forstner bits.

Maybe you need to pick a shorter extension... Now granted I'm drilling out on a lathe. Where the wood moves and the bit is stationary. I'm not speaking from experience here. Just trying to work through the situation in my head.

[wilburpan]

I would like to gives this one a go (trying to improve my hand tool skills) Any suggestions as to buying a bit and brace? Something new. I'm not into the hunting and pecking on Ebay/Craigslist :-)

Unfortunately, that's one of the best ways to get a good bit and brace these days. The options that are out there for new braces are few, and I have yet to read a report from anyone that they loved it. Also, the new braces all have a 10" sweep, and for something like this task you want a brace with a larger sweep.

The good thing is that there are some good sources for used tools. eBay is actually not bad for this. Do searches for "Stanley brace", "Millers Falls brace", and "Yankee brace". A 12" sweep is good, 14" sweep is rarer but even better.

Another alternative is to go to http://www.brasscityrecords.com/toolworks/new%20tools.html , and talk to Walt. Tell him that you want a good 12" or 14" brace, and he'll either get you set up or keep on the lookout for a good brace.

Here's a website with a lot of good info on braces: http://www.sydnassloot.com/brace.htm . THere are also braces there for sale, and I saw a 12" 923 Ratchet Bit Brace with rosewood handles for $35 there. That's a really good deal.

New bits can be gotten more readily. Tools for Working Wood has them.

Hope that helps!

[Chems]

Could your perhaps drill through with a normal drill bit to the other side, then plunge through a bottom bearing guided bit to remove the last bit 1.5"?

I've done this before when I haven't had enough depth to get all the way through.

[AMarshall]

Could your perhaps drill through with a normal drill bit to the other side, then plunge through a bottom bearing guided bit to remove the last bit 1.5"?

I've done this before when I haven't had enough depth to get all the way through.

That's a good one too. Lots of different ways to get the job done, I love it.

[JohnnyNoName]

Could your perhaps drill through with a normal drill bit to the other side, then plunge through a bottom bearing guided bit to remove the last bit 1.5"?

I've done this before when I haven't had enough depth to get all the way through.

I like it!

Jonathan

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[Chems]

That's how I did it here, plunged as far as I could, then jigsawed out the rest:

Then flipped over and bearing guided bit from there to finish off. Similar sort of deal on a small scale.

[bois]

I have always used a brad point bit for drilling bench holes. They are typically much longer than forsner bits and clear chips much more effectively for long holes. They easily clear a 4" thick bench top. They just heat up a lot, so keep a bucket of cold water handy for quenching the bit.