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Feb 23, 2018

How to Drill Perfectly Vertical Bench Dog Holes in Your Workbench

 A woodworking bench is more than just a table to lay your tools and project parts on. Used well, your bench is an all-in-one, three-dimensional clamping solution that will allow you to hold your work on any of its edges or faces. The traditional way to increase the work-holding capability is to place "dog holes" in your bench top, and allowing them to work in tandem with a face or end vise to secure parts of any size.  

In order to work best, these holes need to be drilled vertically... or at a consistent off angle, typically between 2-3°. Normally, when you want a dead-on perfect angle, you'd place the workpiece on the drill press. But if you can figure out how to muscle your benchtop to work under a spinning drill press bit, then mister, you're a better man than I. 

So, instead, we must take the drill to the work, and figure out how to keep our angle nice and consistent while creating clean holes in a beefy benchtop. The answer, as in many woodworking solutions that seek consistency: let's build a jig!  

 

How to: Build a Jig for Drilling Bench Dog Holes

Tools and Materials:

  • 3/4" dog hole bushing (not required, but highly recommended), more below
  • 3/4" auger bit, more below
  • Crosscut saw, drill, and other assorted tools
  • length of 2x4, some 3/4" plywood, and other scraps

 

My approach takes advantage of this ingenious little helper - a steel bushing that prevents your bit from wandering. You don't have to use one, but a guarantee that I won't mess up the benchtop I spent months building is worth $8.40 to me. If you want to try to DIY something with the same principle, look for some steel pipe with an ID of exactly 3/4" and cut it to size.

 

The bushing is sized to work with a piece of wood exactly 1 1/2" thick. Thankfully, that's the thickness of a 2x4, so grab a scrap that will work.

 

 

If you don't have access to a drill press, use a square to guide your drill to bore a 90° with a 1" bit. Keep trying until you get it right on. 2x4s are cheap, and it's okay if your jig has a couple of holes, as long as you mark the right one. 

 

I do have a small benchtop drill press, so I used that to drill my outer hole with a 1" Forstner bit.

 

Next, cut a piece of scrap plywood to make the base. The size isn't as important, as we'll be adding a fence, but make it as long as your 2x4, and wide enough that you'll be able to place the bushing as far in as you want your dog holes. Mine was about 5 1/2" x 8".

 

Attach the base to the 2x4 with countersunk screws. It's important to use screws and not brads or pneumatic fasteners here, since you'll want to be able take it apart to reuse the guide bushing without the fence to drill holes in other places besides the front edge of your bench.

 

Now, determine how far from the front edge you want your dog holes. I researched the heck out of this, and everything I found indicated that drilling them as close as possible is best, preferably within 2". So, I drew my line to make them 2" on center from the edge, or, once drilled, 1 5/8" from the front edge.

 

With that established, mark a line 2" (or whatever you choose), from the center of the guide hole...

 

... and nail/screw and glue a thin strip of plywood to serve as a fence.

 

Lastly, use a scrap block and hammer or a soft mallet to insert the bushing. 

 

Drilling Your Dog Holes

With your inset line marked, mark a nice big cross to indicate the center of each hole. I spaced mine 4" apart, as that's basically the travel of my end vise.

 

To prevent tearout on the backside, clamp or screw a scrap of 2x4 underneath your dog hole line.

 

The proper bit for the job is an auger bit. This will help you power through the thick top while leaving a clean hole. The wide spiral flutes help remove the chips. I used a Wood Owl Ultra Smooth tri-cut bit, and was very happy with the results. You can really feel this dude grab and pull itself into the wood, and it left a great finish. Highly recommended. 

 

Set up the guide over the cross hairs, and check the placement by inserting the brad point of the bit into the jig. Fiddle with it until it hits dead center, and clamp in place. (If you haven't drilled the plywood base yet, you'll need to do that first to see through). Repeat until you've drilled all your holes. If you want to create a second row, just remove the bushing and screw to additional bases. 

 

Potential last step: if you, like me,  used a softwood for your benchtop, the wood around the holes will get all mangled with repeated use, especially on Douglas fir, which is particularly prone to tearout. That won't really affect its functionality, but since I'm using mine for photography, so I decided to add some insurance.

 

I used a router and 45° chamfer bit to soften the edges. I needed to buy a new bit with a 1/4" shank here to get a bearing small enough to fit inside my holes. I'm glad was able to find that 1/4" collet... which I'm pretty sure I have never used in the ten years of owning this thing. 

 

Use a plunge base if you have one. If not, and your router has a pretty soft start, you'll probably be okay. Just test it on some scrap first, like that 2x4 with all the 3/4" holes in it you used to prevent blowout. 

 

And... you're done! I added some in front of my face vise, and down the right leg to support long boards. I also put some in the back leg and side aprons to store my holdfasts and other tools when not in use.

Make sure you keep your bushing guide and all the bases for whenever you want to add more. Write their use with a big black marker so they don't get confused for scrap.

Have fun!

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Rene' Torres on Dec 10, 2018:

Excellent idea ,I have similar gig less sophisticated same principal got the idea from a commercial dowel hole drilling kit I will incorporate some of holding base on my thanks for charing.*( My 3/4" drill bit tip is similar to the one you used but I ground the threads off it to prevent braking my arm )


Chris on Nov 29, 2018:

Hey @David - I think a 3/4 upcut spiral bit in a router will work for your benchtop.

My suggestions for layout are: get them as close to the edge of the bench if you can, and then have a line to correspond with your vise. If your front vise hardware is centered, you might want to offset the hole in your chop so the dog holes aren't immediately over the vise bar. If it's a quick-release, it won't be a huge deal, but it's nice not to need to open the vise to get a bench dog or holddown in the vertical row.

Good luck! Let us know how it turns out.


David on Nov 29, 2018:

@Chris - I have a 1-3/4" thick maple benchtop, I was going to use a 3/4" spiral bit to plunge the dog holes. Overall bit length is 3-3/4" and cut length is 1-1/4". I have a Hitachi 2-1/4 HP router (2-1/2" plunge) and a Triton 3-1/4 HP router (2-3/4" plunge). I would use the Triton and a guide. It definitely wouldn't bore a 4" hole, but I think I could get the 1-3/4" easy enough. I was using 3/4" ply and 3/4" MDF for a top and, well, that didn't work out well at all. I brought the top from Grizzly and haven't settled on a dog hole layout yet. Any suggestions for that?


Chris on Nov 28, 2018:

@David - I think it would depend on how thick your benchtop is. I've never seen a 4" long 3/4" router bit, though they might exist. You'd need a pretty beefy router to spin it, but if everything is sized right, it'd be a solid way to do this. The auger bit would cost less money overall, I think. I'd recommend clamping the router base or making an edge guide so it stays put throughout the cut. If you give it a shot, let us know how it turns out.


David on Nov 27, 2018:

Would a plunge router with a 3/4 bit work as well or better?


Chris on May 10, 2018:

Hey @Dan - That's a *really* great idea. Is 3/4" pipe exactly 3/4" ID?


Dan on May 10, 2018:

You could also make a simple drill guide using black iron pipe. A 3/4" flange and a short nipple (3/4" ID) screwed into it would give you a nice straight guide. Cost would be under $4. Similar solution to an iron bushing, but half the price, and you can make the guide as long as you like to ensure straight holes, especially if your auger bit is long. You can also build a base with multiple guides and drill 2 or more dog holes in quick succession that will always be lined up properly.


Dan on May 10, 2018:

You could also make a simple drill guide using black iron pipe. A 3/4" flange and a short nipple (3/4" ID) screwed into it would give you a nice straight guide. Cost would be under $4. Similar solution to an iron flange, but half the price, and you can make the guide as long as you like to ensure straight holes, especially if your auger bit is long.


Denny on May 06, 2018:

Using a bushing is a great idea. However, if you want to skip using the bushing, make a simple "jig" that will guarantee a perfect fit for drilling bench dog holes. Find a scrap piece of hardwood (ie: oak) about 1 1/2" thick. If you don't have a piece that thick, face glue two or more thin pieces together. Mill this piece ensuring it is flat. Determine the diameter of the bench dog you plan to use then select the matching forstner bit.
Mount bit in the drill press, and drill all the way through the "jig". Using a sharp object, punch small "dimple" marks on your work bench where you want to drill holes. Secure forstner bit in your drill. Fit the forstner bit into the jig and lightly move the jig side-to-side until the point of forstner bit presses into the dimple. Secure the jig to work bench and carefully drill hole. Since you are using the same forstner bit in all drilling operations, a secure fit of the bit in the jig is guaranteed! An additional suggestion. Determine what the measurement will be between bench dog holes then drill a second hole in the "jig" equal to this distance. After the first hole is drilled, place a dowel in the jig and position the dowel into hole just drilled. The next hole to be drilled is easily determined by simply using the second hole in the jig.


Chris on Apr 25, 2018:

@Stan - Good to know. Helpful for all reading here.

Please share a pic of your bench when you're done!


Stan H on Apr 25, 2018:

Solved the problem with new Mag-bit from Tool City here in LA. Perfect fit. Lesson learned : Not all bits are within spec esp IRWIN and Bosch.


Stan H on Apr 25, 2018:

Chris, since I couldn’t insert the drill bit in the bushing I did a fit check by inserting the shaft end of the bit into the bushing. It went in smoothly until it reached the drill bit head. So the cutting points at the end must a little wider. Your WoodOwl bit must have a very tight tolerance. I suppose I could try to file down the end of the IRWIN bit.


Chris on Apr 25, 2018:

Hey @Stan - Thanks for your question. I'm sorry to hear about your problem.

I don't believe there's anything special about the WoodOwl bit in that regard. Could you say a little more about this line "the shafts go all the way through until you reach the head and they jam"? The head of what part?


Stan Hendrix on Apr 25, 2018:

I have run into a unexpected problem. I have tried two 3/4" auger bits (Irwin and Bosch) and neither fits through the bushing; the shafts go all the way through until you reach the head and they jam. 3/4" forstner, spade and an all-purpose back oxide buts all fit through the bushing cleanly. Is there something special abut the WoodOwl bit you are using?


Sharon D. Quinn on Mar 12, 2018:

Thanks for sharing this article and could we use any other tool to measure perfectly.


Chris on Jan 23, 2018:

Hi Barry,

I have row of dog holes in line with my vise. I use them all the time.

The thing you need to be aware of is lining up the holes so they don't hit the vise screw. This can be accomplished by offsetting the hole in your chop to either side to avoid it. While it's not a huge deal with a short bench dog, a longer device like a holdfast will hit the vise screw.

If you're concerned about drilling into the hardware, just full extend the vise, and there will be no problem. As far as chips and dust on the screw and grease: yeah, it does happen, but to me that's a small price to pay for the convenience of having the row of holes there. I haven't yet had to clean or regrease, but I'll just do it when the time comes. I try to keep fine dust in the vacuum at all times, so it's mostly just chips and shavings. If you're concerned about it, you could make a planing stop that connects to your front vise that covers all the holes, which keeps the crud out.

Great question! Let us know how it turns out.


Barry on Jan 23, 2018:

It would seem to make sense to drill bench dog holes behind your woodworkers vise so that you would hold down work pieces using the vise on one end and a bench dog or two at the other end. However, it would seem risky to drill down through the bench top when the 3 threaded metal vice rods pass below. Also I'd foresee sawdust and chips getting onto the greased threads of the vice rods. Any advice here?


paulie on Sep 04, 2017:

For a second and other subsequent rows of dog holes, mount your 2x4 hole guide on a jig that has two 3/4" holes drilled to line up with the first row. In your case 4" from the guide and 4", 90 degrees back. Jig looks like an 'L' shape with peg hole, peg hole on front edge and guide bushing for second row. 3/4" pegs through the holes in the (front) edge row keeps you at the right distance and square as you drill, move up, 'repeg' and drill the next hole.


Chris on Feb 09, 2017:

Hi Larry,

I did drill a row of holes behind the face vise at the same time. I simply made another plywood base with fence and referenced it off the end/side of the bench, as you suggested. The trick was simply to make sure the guide bushing was aligned right over my mark, and that the base was clamped down securely. With this technique and being able to use all four sides of the bench, I think I'd be able to accurately drill a hole anywhere on the benchtop.

Thanks,
Chris


Larry D Dobbins on Feb 08, 2017:

This illustrates drilling dog holes along the front edge of the bench. Great job! You probably want to add one or two more rows of holes behind the first for your end vise. And you probably what holes that go all the way back behind your front vise. But adding suggestive rows of holes behind the first row, so they align perpendicularly with the front of the bench, is a whole new challenge. Yes, the jig base could be widened to accommodate one or two subsequent rows behind the first row. But to keep the successive rows perpendicularly aligned with the front, so your grid of dog holes are square with one and other, aren’t you going to have to also index off the end of the bench?. How would you do that?