Reader Robert Monetti writes: Loved your presentation on workbenches, and now I am inspired to design and build my own. I know you can’t believe this, but the only information that is missing is: What are the best shapes for dog holes, round or square? I think square would be better for offering more friction but are direction limited when using clamping dogs.
If round, what diameter? If square or rectangular, what length and width? It would also be helpful as to there location and the orientation of rectangular holes.
Give me answers to these questions and I am on my way local mill house.
— Robert Monetti
Robert: Your questions will fetch a variety of valid answers. After working with both round and square dogs, I have my preferences. But both systems – round and square – work and work quite well. That said, here’s my argument.
I like 3/4”-diameter round dog holes. They are simpler to install during construction of your bench and even after construction. Round dog holes handle a wide variety of modern workbench accessories: hold downs, holdfasts, Wonder Dogs and the like. And you can turn the dogs 360° to clamp odd-shaped pieces.
The downside to round dogs is that they are usually brass or other metal, which can be dangerous to your tools. You can make wooden round dogs (use a tough wood), but I have used metal round dogs for more than a decade with only one minor incident to report.
Place the Dog Holes
So where do you put your dog holes? In general, I like to bore as few as possible. I have a couple dog holes in my benches that I never use. They are, after many years of disuse, like an unfortunate tattoo. They seemed like a good idea at the time. And why they don’t hurt much, they don’t add anything and are a reminder of an evening of wild boring (if that oxymoron is possible).
I use two lines of dog holes. One is for an end vise and one is for holdfasts. If you have an end vise (such as a tail vise), then bore a long line of dog holes near the front edge of your benchtop. Typically, this line of holes is located between 2” and 6” from the front edge. I like 4” – which allows me to clamp a 8”-wide board in the center. I have an 8” power jointer, so this makes sense for me.
I place these holes on 3” centers or so. Closer together is better for this line of dog holes because closely spaced dog holes will prevent you from screwing and unscrewing your tail vise as much.
The rear line of dog holes is different. It is mostly for holdfasts, and their spacing is determined by how far the pad of the holdfast is from the shaft. If this distance is 8”, than placing your holes every 16” (maybe a little less) allows you full coverage along the rear of your bench.
This line of holes should be located about 6” or so from the rear edge of your bench. That will allow you to rotate your holdfasts for a variety of holding situations. That should get you started.
— Christopher Schwarz
2 thoughts on “The Better Dog Hole: Round, Square and Where?”
Thanks Chris, this information has been duly noted in my list of things-to-consider-before-I-start-to-build-my-workbench.
I, too, use 3/4" round holes, but I have a lot of them on my bench. I’m building a boat and so little is square that the multiple holes allow for easier clamping of curved items.
In addition to the brass bench dogs, I’ve made a number of wooden dogs. The cylindrical vertical portions are made of sawed-off pieces of hardwood dowel. The square tops are made of some left over poplar. I’m not near my shop right now, but I think the squares are about 2" x 2", but the important part is that the tops are of various thicknesses (1/4", 1/2", and 3/4"). That way when I’m planing I don’t plane off the tops of the dogs.
Dan in Tallahassee
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