¾ or 20mm Bench Dog Holes (What’s the Measurement?)

Bench dog holes are a crucial part of woodworking projects. They help you to secure the bench dogs.  But you are seeing confusing measurements around the measurement for dog holes. It’s okay, we were confused when we started too.

So, either ¾ or 20mm Bench Dog Holes. Which one is ideal for bench dogs?

If you’re wondering either ¾ or 20mm bench dog holes, they are almost the same measurements. When you convert 20mm into inches, it’s ¾ inches and vice versa. And yes, the thickness of the bend dog holes should be ¾ inches. Drill this thickness of a hole in perpendicular to your workbench surface. 

For beginner carpenters, the summary above surely isn’t enough. In this article, we’ll talk about the different measurements of bench dog holes. And how to make them and more.

Follow along with us!

What are ¾” and What are 20mm Bench Dog Holes?

3/4 inch dog holes are the most common dog holes used on workbenches. Woodworkers typically use dog holes to make their work benches more functional. The holes are used to clamp down the wood pieces with clamps through the holes. 

20mm measurements for a workbench dog holes are less common. When converted into inches, it’s 0.78 inches. So, 20mm dog holes are slightly bigger than ¾ inch dog holes. The function of 20mm bench dog holes is the same as ¾ inch bench dog holes.

For each size of dog hole, you’ll need to purchase the appropriate size of bench dogs. Otherwise, they won’t serve the purpose as efficiently. The clamps, planning stop won’t be able to hold the wood piece as tightly in place.   

The correct mm conversion of ¾-inch bench dog holes is 19mm bench dog holes. Which amounts to .748 inches which is closer to ¾ inch dog holes. 

So if you want to use the same bench dogs or clamps of ¾ inch. You can use them for 19mm bench dog holes.

How to Make ¾ or 20mm Bench Dog Holes

Now we know how functional these ¾ or 20mm bench dog holes are for workbenches. 

Here s how you can easily make ¾ or 20mm bench dog holes on your workstation. 

Tools Needed to Make ¾ Inch or 20mm Bench Dog Holes

Gather these tools to prepare to make holes in your workbench – 

  • A corded or cordless plunge router
  • Pegboard with ¾ or 20mm holes
  • Marker
  • Square
  • Paddle bit or Spade bit
  • Drill Machine

Let’s get down to making holes

Step 1 of 2: Measure and Mark the Places for Holes

Take the pegboard and place it horizontally on your workstation. Now mark the number of holes you want to make on your peg board. 

The ideal distance between each bench dog hole is about 3-4 inches. However, you can maintain whichever distance you see fit for your convenience. 

Take a marker and mark your workstation through the pegboard. This will make the process easier when you are drilling holes. 

However, you can also make your own pegboard with a ¾-inch thick metal sheet. The Benefit of doing so is, you can create the template as you wish. On the template, you can make either size holes. Either ¾ inch, 19mm or 20mm holes as you need. 

Another benefit is that you won’t have to remove the template. While you are boring holes in your workstation with the template on top of the surface. In This case, you also don’t need to mark the places where you want holes.

Step 2 of 2: Drill the Dog Holes

Take the drill machine. And attach the ¾ inch or 20mm spade bit to your drill machine. Remove the peg board. Place the square beside the marking. This will help you align your drill machine. 

And you’ll be able to drill holes perpendicular to the workstation. Remember, failure to drill holes that are perfectly perpendicular will not be functional. Poplar wood can be a good option for a workstation.

Place the spade bit onto the markings and start drilling holes carefully. Repeat the process until you have drilled enough dog holes you need.

On the other hand, if you’re using a plunge router. Attach a ⅝” screw bits to your router. Place the plunge router appropriately and start drilling holes. 

As opposed to the drill machines, corded or cordless routers are convenient for bench dog holes.

Bench Dog Hole Options For ¾ or 20mm Workbench Dog Holes

There are two options for your bench dog holes –

  • Purchase metal dog holes
  • Make your own wooden dog holes

If you purchase metal dog holes, there are a variety of options online and offline. You can easily find ¾-inch dog holes in these workshops. 

On the other hand, you can also make your own bench dog holes. For that, you only need to buy ¾ inch or 20mm dowels. Then make your own dog holes according to your need. 

Making Your Own Dog Holes

Here’s how you can easily make your own bench dog holes.

  • Place the dowel firmly and hold it down vertically. 
  • Mark from where you want to cut out a notch. The ideal length is an inch or so. 
  • Use a back saw to cut a horizontal line against the grain
  • Take a wide chisel and nibble off the excess wood.
  • Shape them according to your wish

The Pros of handmade wooden dog holes – 

  • They are cheap
  • Easy to make
  • You can customize your dog holes
  • Your tools will be safe if you don’t push the dog holes enough when it hits. Which often happens with metal dog holes.
  • Round bench dogs are easier to add than square bench dogs.

How to Prevent Bench Dog Holes From Falling Through

Oftentimes, bench dog holes fall through the workbench. There’s a small trick you can use to prevent that from happening. 

Which is, using a bullet cabinet door catch. 

Here’s how you can use the trick – 

  • Create a small hole at the side of the bench dog
  • Epoxy or glue the bullet cabinet door catch 
  • Use a carving gouge so that the door catch doesn’t stick out too much.

This will securely hold the bench dog inside the hole. 

Clamping Options for ¾ or 20mm Bench Dog Holes

There are multiple options for clamps to use in the bench dog holes. You can also convert your bench dog holes to make holdfast holes for using holdfasts. 

The difference for holdfast holes is that you need to bore a bigger hole behind. The ¾ hole you bore on top of the workbench, bore a hole slightly bigger on the back. This gives more space for the hold fast to wedge itself. A corded router lift can help you with this.

There are different types of clamps you can use in place of bench dog holes. The clamps help to keep the wood piece tightly in place. So when you’re using an iron hand plane or other tools, they don’t come in contact. 

Pipe Clamps

The cheapest clamps you can own are most likely pipe clamps. You must first purchase these jaws separately before purchasing the desired pipe length. 

You can get these with threads already attached at the ends. They can be found at the majority of home centers, lumber yards, or hardware stores. They are sold to suit 12″ or 34″ black pipes.

Bar Clamps

Bar Clamps are one of the most versatile clamps out there. They come in 3 different sizes. You can use them for gluing, holding stop blocks, or as a third hand.

They can be used in almost every kind of woodworking project. You’ll see it for yourself when you start working with it.

Strap Clamps

Last but not least, this is an odd choice, but a strap clamp is crucial. The best approach is to square everything up. When you need to glue something together that has four sides, like a box. Use a strap clamp. It’s also useful when working with a cordless router lift.

It will shock you how useful this clamp is and how frequently you’ll use it.  


How Thick Should A Bench Top Be For Dog Holes?

You can choose to utilize 1″ or 3/4″ holes for your bench dogs. And 3/4″ are more typical. Drill the holes precisely perpendicular to the workbench surface. Or else your bench dogs won’t function properly when you drill the holes in your workbench. It’ll construct a jig to help you line your drill.

Where Do You Put The Holdfast Hole?

The hole that is to be dug first is the one on the left-rear side. It should be about 8″ from the left end of the workbench. And 4″ from the back border of the bench. Position this hole directly so the holdfast’s tip is directly in front of your planning stop. and it extends to the right. 

What Are Workbench Dog Holes?

Dog holes are normally spaced 4 to 6” apart. And are positioned in a line perpendicular to a vise’s jaws. To allow wide or lengthy things to be held fast in two directions. As well as to the benchtop itself when utilizing one or more holdfasts. Some workbenches incorporate a second row parallel to the vice jaws.


So, that was all about ¾ or 20mm bench dog holes. As you can see, regardless of the measurement, they are a very important part of woodworking. 

Did the article help you clear out the confusion? What size of bench dog holes will you need? 

Best of luck with your woodwork!

Kevin Smith

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