How to bore dog holes

[Rolf Safferthal]

My workbench project develops. Thats the good news, Another good news from this forum is, that the 3/4 inch round bench dogs will work in 20 mm bores too! (I´m European)

The workbench top will be 2 5/8 inches European Beech. In my opinion it might be not that easy to drill the bores with a column drill machine. Freestyle by hand seems much easier, but I expect difficulties to do them exactly rectangular.

There must be an easy solution. Can anybody give a hint, please?

Rolf

[Chris Barton]

Hi Rolf,


Why not use round dogs? That means you get away with drilling your holes and you are done. I have them on my bench and they work great and most bench dogs I see over here are made for round holes.

chris

[Alan Turner]

Rolf,
I think you are asking how to accurately bore holes of this size, not using a drill press. What I do in this situation is to make a drill guide by using the drill press to bore the same size hole, in this case 20mm, in a piece of scrap, maybe about 50mm thick. Make the guide block large enough that you can get a clamp or two on it. Clamp it in place, an it will orient you drill bit correctly. I would use a forstner bit for this size hole in thick hardwood. Drill as far as possible with the guide in place, and then remove it and finish the hole.

If these are to be along the edge of the bench, each being equidistant from the edge, then size the guide block so that the pilot hole is exactly the distance you want the ultimate holes to be from the edge of the bench, and attach a side piece (nail on a scrap) that hangs down, and registers it from the edge. All your holes will be aligned correctly in this manner.

[James Biddle]

If you are building a laminated top, you can bore the holes in individual strips before the glue-up. leave the strips a little longer so you can align the holes during glue-up and trim the ends of the slab after glue-up. Then you can chamfer the holes with a cordless or hand drill after flattening the slab.

[Maurice Ungaro]

Rolf,
I think you are asking how to accurately bore holes of this size, not using a drill press. What I do in this situation is to make a drill guide by using the drill press to bore the same size hole, in this case 20mm, in a piece of scrap, maybe about 50mm thick. Make the guide block large enough that you can get a clamp or two on it. Clamp it in place, an it will orient you drill bit correctly. I would use a forstner bit for this size hole in thick hardwood. Drill as far as possible with the guide in place, and then remove it and finish the hole.

If these are to be along the edge of the bench, each being equidistant from the edge, then size the guide block so that the pilot hole is exactly the distance you want the ultimate holes to be from the edge of the bench, and attach a side piece (nail on a scrap) that hangs down, and registers it from the edge. All your holes will be aligned correctly in this manner.

To take Alan's suggestion further, wshat I did was to bore two holes in the guide block, making sure that the spacing I wanted was proper. Then, after drilling the first hole in the bench top, take one of the bench dogs, and run it through the guide and the bench top. Now, drill the second hole, and repeat, by registering each new hole with the last one drilled. Hint - make sure the first hole lines up with the dog on the shoulder vise AND the dog on the tail vise.

[Jim Becker]

Carefully! It's no fun to have to fill them and redrill. Trust me...I know.

I actually drilled mine with a brand-new Irwin spade bit...the one with the sharp little "ears" that pre-slice the fibers. I got very clean cuts with it, but did have to hone the edge every 6-8 holes in 2 1/8" thick hard maple.

[Rolf Safferthal]

Thanks for the suggestions!

The top is massive European Beech and it ist 2 5/8 inches thick.

Yes I also thought about such an drill guide as Alan suggested. But I cannot see how such a guide may help with a forster drill? At the moment the drill sinks down into the top it loses guidance due to the fact that the following shaft is much thinner. The bores might go wrong.

I have noch experience with these Spade bits, but will try one to get an idea how it works.

How about Brad Point Drill Bits?

Rolf

[Steve Cox]

I used an auger bit at a very low speed with an 18V Bosch cordless this time and it worked fine. The last time I had to this operation I used an auger bit with a brace and it worked fine also (just a lot slower:) ) I made my guide the way Maurice suggests.

[Russ Filtz]

I second the use of a ship's auger bit. Cuts clean and faster than a Forstner or spade for this type of application.

[lloyd morris]

Rolf,

I used round bench dogs from Lee Valley in my workbench and have been very pleased with the result. They grip well without marring the project, hold their place in the workbench top and are easy to drill with a simple jig I made from scrap pieces. Hope this helps.

Lloyd Morris

[Timo Christ]

Hallo Rolf,

i recently drilled alot of 20mm holes in my portable bench, 60mm sheet good top (OSB+Plywood). I used a long 20mm wood drill bit (Holzbohrer aus dem Baumarkt :) ) and a portable drill press. The holes came out straight and true and i use 20mm bench utilities (DIY "wonder dogs", M20 threaded rod, wooden bench dogs) in them.
The long straight drill bit will be much more stable than a forstner bit esp. with extension shaft.

Regards
Timo

[Tony Shaftel]

I ordered a 3/4" brad point bit from Lee Valley for exactly this purpose--had to wait til they were in stock. I was thinking of using a spade bit, but the two different brands I bought produced a slightly oversize hole. Perhaps this would make no difference in the end, but I decided to use the brad point.

[Timo Christ]

Brad point bit! Exactly the term i didn't know.. :) and the right tool for the job.
Thanks!
And i used this portable drill press (http://www.amazon.de/exec/obidos/ASIN/B0001KNIXU/ref=br_lf__4/302-8226670-4469653).

[Alan Turner]

I was thinking Frostner, becuase that is what I have, but a brad point would be much better.

[Michael Perata]

Rolf

I used this http://www.toolpeddler.com/36-37.htm to drill the holes in my bench.

I used a spade bit with a spur for the holes.

[Dan Forman]

This thread couldn't have been more timely, as I need to do the same thing on my bench. I just went down and did a few sample holes using my 3/4" auger bit. I found the results unsatisfactory, even with the "portable drill press" which mine, in all fairness, is a bit flimsy, and appears out of alignment in the non-adjustable direction. My pdp looks just like the one that Michael just posted the link to. It may be a knockoff though, doesn't have a brand name on it. Mine is anything but precision, has a pronounced wobble with the drill installed.

It seems the auger bit exerts quite a bit of lateral force as it is digging in to the work surface (I practiced on a cutoff from my bench, which is a solid core [particle board core] door). None of my test holes, with or without the pdp, were perpendicular to the top. I found the auger bit VERY difficult to control without support, and even using hole drilled in a 2x4 (with my real drill press and a forstner bit) for a guide, the hole was not perpendiular to the table, and the guide hole had been deformed by the lateral force of the auger bit.

I will soon be going out to pick up a brad point bit and see if I have better luck with that, and report back.

Dan

[Michael Perata]

Dan

The General Tool I posted on is not flimsy, but it is not a drill press either. I found it very stable when used perpendicular to the stock being drilled. The chuck is not great, but it worked.

[Chris Padilla]

Rolf

I used this http://www.toolpeddler.com/36-37.htm to drill the holes in my bench.

I used a spade bit with a spur for the holes.

:D I know where to borrow one to drill dog holes for my bench now.... :D

[Rolf Safferthal]

Hallo Rolf,

i recently drilled alot of 20mm holes in my portable bench, 60mm sheet good top (OSB+Plywood). I used a long 20mm wood drill bit (Holzbohrer aus dem Baumarkt :) ) and a portable drill press. The holes came out straight and true and i use 20mm bench utilities (DIY "wonder dogs", M20 threaded rod, wooden bench dogs) in them.
The long straight drill bit will be much more stable than a forstner bit esp. with extension shaft.

Regards
Timo

Hi Timo,

another guy from Germany! ;) And - funny - with more or less the same profession!



The same kind of drill guide Chris and Michael mentioned is available from a German Company (Wolfcraft) but my experience with other products from this manufacturer is pretty mixed. I might give it a try but I´m not overoptimistic.

Yesterday evening I learned that it might be possible to use my drill press for the job. I can modify it that way that the drill is on the back side of the column - away from the ground plate. The only problem, without some kind of fixation the whole thing is unstable and tips.

Thanks to all for their helpful answers!

[Dan Forman]

Yesterday I picked up a 3/4" brad point bit (interestingly enough made in Germany), and found it more manageable than the auger bit. With the less than perfect portable drill press, it did a pretty good job of drilling a hole perpendicular to the plane of the bench top. It doesn't generate near the lateral force of the auger bit. With either the pdp or a hardwood drilling guide, this should do the trick.

Dan

[Hank Knight]

Rolf, I used Alan's method to drill all of the dog holes for my bench, but I used a new, sharp 3/4" brad point bit instead of a forstner bit. My top is 3" hard maple. It worked great. The only additional suggestion I would offer is to clamp a piece of wood, preferably hardwood, to the underside - where the hole will exit - to reduce splintering when the drill bit breaks through.

[Norman Hitt]

Rolf, if you have a plunge router and either a plunge cut straight bit or a spiral bit of the proper diameter and a 1" Guide Bushing, just make a jig for hole location, and then make the initial plunge cuts to the max depth of the router bit on all the holes. Since the bit will probably not be long enough and the router not be able to plunge that deep, you will then need to remove the jig and finish drilling through the table top with a bradpoint bit.

The initial hole made by the router bit will be perfectly perpendicular to the table top, and that hole will guide the bradpoint bit and keep it straight on through the remainder of the wood. As mentioned previously, clamp a backer board on the bottom to prevent tearout as the bit exits the wood on the bottom.

[Rolf Safferthal]

Norman, I´ll give that a try! Sure that will make a perfectly perpendicular hole.


My router has a plunge depth of 55 mm, so it can reach nearly 50 mm in depth. Needs a pretty long bit! Hope, I can get one long enough.

[Chris Padilla]

Perhaps a silly question:

Do dog holes (round or square) normally go through the entire bench top? Obviously, dog holes in the bench side skirts do not but what about the top?

[Andrew Ault]

Hey Chris,

In my experience, they must go all the way through the top so dogs can be adjusted up and down. Usually, the dogs I use stick out of the bottom of the top. For instance, if I'm planing something, not much of the dog sticks up above the surface of the top and much of the dog is sticking out of the bottom.

-Andy

[Mike Weaver]

Perhaps a silly question:

Do dog holes (round or square) normally go through the entire bench top? Obviously, dog holes in the bench side skirts do not but what about the top?

Chris,
Yes, they usually go through the top. It'd be a REAL pain to have to clean out shaving/chips, etc from them otherwise. I won't even mention the question of how to get stuck dogs out either... Oops, i just did. :eek:

Cheers,
-Mike

[Dan Forman]

Lee Valley "Bench Pups" are designed to be used in situations where it isn't convenient to go all the way through the top, such as if there are drawers directly under the top of the bench. Two inch holes are recommended, which leave about 1/2 inch of pup above the surface. They are simple enough to pull out, and a shop vac will make short work of any debris that falls into the holes.

Dan

[Don Stanley]

Rolf

I used this http://www.toolpeddler.com/36-37.htm to drill the holes in my bench.

I used a spade bit with a spur for the holes.

I consider this tool a must-have for any shop! I have had a fixed base version for years, and it gets a lot of use. I replaced the chuck on an old 3/8" drill with a 1/2" chuck, and dedicated it to the fixture.

-Don

[Norman Hitt]

I consider this tool a must-have for any shop! I have had a fixed base version for years, and it gets a lot of use. I replaced the chuck on an old 3/8" drill with a 1/2" chuck, and dedicated it to the fixture.

-Don

When this tool first came out, (I don't remember who made it), but it had an aluminum base that was fixed at a 90* angle, and I bought one within two days after it hit the stores, (must have been 35 + years ago), and I found it so useful that I bought my Dad one also for X-mas, and we both dedicated a drill to the unit. I didn't have a drill press then, and It got a LOT of use, and although the drill press gets most of the work now, it is still in my shop and still gets used for lots of things that are just not easily done with the drill press, but accuracy is needed for both perpendicularity and the depth stop can't be beat. The builtin centering jig for drilling round objects like dowels, pipe, etc was also Very handy.

I think I paid something like $14.95 for the first one and a few months later they were $19.95 when I went to buy Dad's. I guess they sold so many they must have figured they had them priced too cheap, because back then I don't remember seeing "Introductory Prices" on hardly anything related to tools when they first came out, (at least out here in our part of the world). :D

[Hank Knight]

When this tool first came out, (I don't remember who made it), but it had an aluminum base that was fixed at a 90* angle, ...

Norman, I think the original brand name was "Portalign" or something like that. I bought one of the originals and still have it and use it. I recently bought one of the newer adjustable models, but I dont think it is nearly as sturdy as the original. Glad I kept the old one.

[Norman Hitt]

Norman, I think the original brand name was "Portalign" or something like that. I bought one of the originals and still have it and use it. I recently bought one of the newer adjustable models, but I dont think it is nearly as sturdy as the original. Glad I kept the old one.

You're Exactly Correct on the name, "Portalign", Hank. Thanks for Jogging my Memory. I still don't remember if that was the name of the Company, or just the name of the tool, though. Mine is still accurate too.

[lou sansone]

I will assume that some one mentioned to "back up" the hole in the bottom of the bench top to prevent splintering. If you do decide to use a ships auger ( which I would in combination with a fostner bit to get the nice looking hole started) you would need that added material for the self feeding screw.


lou

[Bryan Schneider]

Could mount the drill guide in the above post to a piece of wood like the jigs above and have a self indexing setup that drills perpendicular to the surface. 3/4" MDF would probably be fine for the base.