Drilling Bench Dog Holes: Layout, Spacing, and the Tools That Actually Work

Plenty of workbenches sit for years without dog holes. That means clamping everything to the edge, fighting pieces that want to spin, and cursing under your breath every time something has to be held flat for planing. The day those holes get drilled is the day a workbench becomes a real woodworking tool instead of an expensive table.

If you have been putting off this task because you are afraid of messing up your bench top, this guide is for you. I have drilled dog holes in five different benches now and learned something new each time. Here is everything I wish someone had told me before that first hole.

Round vs Square Dog Holes

Round holes are the modern standard. They are easy to drill, accept a huge variety of commercial bench dogs and holdfasts, and work with every aftermarket clamping accessory on the market. A 3/4-inch round hole is the universal size that fits Veritas dogs, Lee Valley holdfasts, Gramercy holdfasts, and most bench-mounted clamps.

Square holes are traditional and found on European-style benches. They require a mortise chisel to cut, take much longer to make, and only accept square bench dogs. Unless you are building a historically accurate Roubo bench and own a set of square dogs, go with round holes. The versatility alone makes them the better choice for 99 percent of woodworkers.

How Many Holes and Where

You need two rows of dog holes for most workbench operations. The first row runs along the front edge of the bench, about 3 inches in from the edge. The second row runs parallel, about 8 to 10 inches behind the first. This spacing lets you clamp wide boards flat between dogs on both rows.

Space the holes about 4 to 6 inches apart along each row. Closer spacing gives you more clamping positions but weakens the bench top. Wider spacing means fewer holes but occasionally you cannot get a dog close enough to your workpiece. A 5-inch spacing is the compromise that works well for everything from small boxes to wide panels.

The front row should extend the full working length of your bench. The rear row can be shorter, about two-thirds of the bench length is usually enough because the tail end rarely needs rear dogs.

Depth Matters

Dog holes need to be deep enough to hold a dog or holdfast securely but not so deep that they go through the bench top. For a standard bench top that is 3 to 4 inches thick, drill your holes about 2.5 to 3 inches deep. This gives holdfasts enough shaft length to grip properly and keeps bench dogs from falling through.

If your bench top is thinner than 3 inches, you will need to drill shallower and use shorter dogs. Holdfasts require at least 2 inches of shaft depth to work reliably, anything less and they will not grip. If your bench is under 2.5 inches thick, consider bolting a hardwood strip underneath the dog hole row to add depth.

Layout Method

Do not eyeball your hole positions. Mark them carefully with a tape measure and combination square. Snap a chalk line or use a long straightedge to mark the row centerlines first. Then mark individual hole centers along each line at your chosen spacing.

Use a center punch or awl to make a starter dimple at each mark. This prevents the drill bit from wandering when you start the hole. On a hardwood bench top, even a sharp Forstner bit will skate sideways without a starter mark, and a wandering hole on your bench top is there forever.

Stagger the rear row holes so they fall between the front row holes rather than directly behind them. This gives you more clamping positions and avoids creating a line of weakness across the grain of the bench top.

Drilling Methods Ranked

Best: Drill press. If you can get your bench top under a drill press, this produces the straightest, cleanest holes with zero effort. Use a 3/4-inch Forstner bit at low speed with the depth stop set. The holes will be perfectly perpendicular and identical in depth. The problem is that most bench tops are too large and heavy to maneuver under a drill press.

Great: Portable drill guide. A drill guide clamps to the bench surface and holds a hand drill or cordless drill perfectly vertical. This is the most practical method for most woodworkers. The Big Gator V-DrillGuide and similar products work well. Clamp the guide at each marked position, drill, move to the next hole.

Good: Hand drill with care. You can drill acceptable dog holes with a cordless drill and a Forstner bit if you are careful about staying vertical. Use a small square stood on end next to the bit as a visual reference, check from two perpendicular angles as you drill. The holes will not be as perfectly straight as with a guide, but dogs and holdfasts are forgiving of a degree or two of deviation.

Drilling Without Tear-Out

Tear-out around the hole rim is the biggest cosmetic problem with dog holes. Hardwood bench tops are less prone to this than softwood, but it can still happen with dull bits or aggressive feed rates.

Score a circle around each hole position with a sharp knife or compass before drilling. This severs the wood fibers at the rim so the bit does not pull them out. On a bench top that has already been finished, this step is essential, tear-out through a finish layer looks terrible and is hard to repair.

Use slow speed and moderate pressure. Let the Forstner bit do the cutting rather than forcing it through the wood. Clear chips frequently by lifting the bit out of the hole every half inch of depth. Packed chips generate heat and cause burning, which hardens the hole walls and makes dogs fit poorly.

After Drilling

Clean up each hole with a slight chamfer around the rim. A countersink bit, a chamfer bit in a router, or even a few swipes with sandpaper wrapped around a dowel all work. The chamfer prevents the hole edge from chipping during use and makes inserting dogs easier.

If you have finished your bench top, apply a coat of your bench finish inside each hole to prevent moisture from entering the end grain. Paste wax works well inside the holes, it also makes dogs slide in and out smoothly.

Test every hole with your dogs and holdfasts before calling the job done. A holdfast should lock solidly with one sharp tap of a mallet. If it slips, the hole may be slightly oversized, line it with a thin strip of leather glued to one side to tighten the fit.

The Holes You Will Wish You Had

After using your bench for a few months, you will discover positions where you wish you had a dog hole. That is normal. Leave yourself permission to add holes later, that is the beauty of round dog holes. You can drill a new one in two minutes whenever you need it. The worst thing you can do is over-plan and drill forty holes on day one. Start with the two rows and add individual holes as your work reveals where they are needed.