What's inside
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Start with the work you do
Bench dog holes are useful only when their diameter and layout match your clamps, stops, and workholding habits. Before drilling a new top, check the diameter of the dogs and hold-downs you already own, or plan to buy. Then consider what you need to secure: narrow boards, cabinet parts, hand-planing stock, or occasional assembly jobs call for different layouts.
For many general-purpose woodworking benches, 3/4-inch holes on a 4-inch grid are a practical starting point. That does not make them universal. Some hardware is designed around 20 mm holes, and some benches use larger holes for specific holdfasts. Mixing standards can leave you with accessories that wobble, bind, or simply do not fit.
Choose a diameter that fits your hardware
Measure the shank of the actual accessories you expect to use; do not rely only on a package label. A dog should slide into its hole without force but have little side-to-side play. A hole that is too tight can seize when dust or finish gets inside. One that is too loose lets a dog lean under load and can bruise the workpiece or reduce clamping reliability.
| Hole diameter | Typical fit and use | Main trade-off |
|---|---|---|
| 3/4 inch (19.05 mm) | Common choice for many bench dogs, stops, and holdfasts | Broad accessory availability, but check that every accessory matches this standard |
| 20 mm | Metric-system dogs and compatible holdfasts | Close to 3/4 inch, but not interchangeable; 0.95 mm difference can matter for a snug fit |
| 1 inch (25.4 mm) | Some larger holdfast and heavy-duty workholding setups | More material removed and fewer compatible accessories than common 3/4-inch systems |
Do not choose 3/4 inch simply because it is familiar if your preferred holdfast needs a different bore. Check the accessory maker’s specified hole size and the required bench thickness. Holdfasts depend on a close fit and a little flex in the worktop; the wrong diameter may make one slip or refuse to tighten. If you have no hardware yet, compare 3/4-inch bench dogs and holdfasts with metric alternatives before committing to the drill bit.
Pick spacing for useful reach
Hole spacing controls how precisely you can position dogs and stops. A 4-inch grid is common because it gives reasonable adjustment for everyday planing and clamping without putting an excessive number of holes in the top. A 3-inch grid offers finer positioning for small parts and narrow stock, but adds drilling time and leaves more holes to collect dust. A 6-inch grid is quicker to lay out and may suit rough work, though it can leave a dog too far from the edge of a short board.
Think about the smallest part you routinely clamp. With a 4-inch grid, a short workpiece may not land near a useful pair of holes. A finer grid can help, but a row of holes near the front edge or an auxiliary fixture may be a better answer than drilling the entire top densely.
| Spacing | Best fit | Trade-off |
|---|---|---|
| 3 inches | Small parts, flexible positioning, detailed handwork | More holes, layout effort, and opportunities for chips or glue to enter |
| 4 inches | General-purpose benches and mixed hand-tool work | May not give an ideal position for very short or unusually shaped stock |
| 6 inches | Large workpieces and a simpler, less perforated top | Coarse adjustment; accessories may be awkwardly far from the work |
Plan the layout around the vise
Start with the front vise, if the bench has one. Mark its dog position and plan a matching row of holes in the benchtop so a board can be held between the vise dog and a bench dog. A typical layout has a row parallel to the front edge, often about 2 to 3 inches behind it, with holes spaced along the bench. Confirm that the vise dog lines up with the row through its full travel.
Leave enough edge material for strength. A hole too close to an edge can split or chip the top, especially in a thin or brittle surface. As a cautious starting point, keep hole centers at least 1.5 to 2 hole diameters from an unsupported edge, and increase that distance if the top is thin, damaged, or made from material prone to splitting. Avoid placing holes through the vise hardware, bolts, embedded metal, or a weak glue joint.
For a tail vise, add a second row only if it helps your actual workholding setup. Two aligned rows can support wider panels with dogs, but the extra holes cost time and reduce uninterrupted work surface. Lay out holes with a story stick or full-size template and check every position against the vise, apron, and base before drilling.
Drill clean, consistent holes
Use a drill guide, drill press, or a rigid jig to keep holes square to the surface. Even a small angle can make a dog lean and spoil a carefully aligned row. Drill a test hole in scrap of the same thickness and material, then try the actual dog and holdfast in it. If the fit is tight, adjust the setup or use a suitable reamer rather than forcing hardware into the bench.
Back up the underside with scrap to reduce tear-out, and clear chips as you drill. Forstner bits cut cleanly but can overheat or wander if pushed too hard; a sharp bit and steady feed help. If the top is thick, drill from both faces to meet in the middle, using a guide on each side to reduce breakout and alignment error. Chamfer the top edge lightly so dogs enter easily, but do not create a deep funnel that lets them rock.
Keep the holes usable
Bench holes collect sawdust, finish, and glue. A simple shop-made tapered plug or purpose-made cover keeps debris out when the bench is not in use. Avoid sealing the inside with a thick finish that can shrink the opening; test any finish on a scrap hole first. If a dog starts sticking, clean the bore before sanding it larger. Enlarging a hole is easy; restoring a snug fit is not.
For a first bench, a 3/4-inch system at 4-inch spacing is a sensible default if compatible accessories are easy to obtain where you live. Choose 20 mm or 1-inch holes only when your planned hardware calls for them, and use a closer grid when small-part positioning justifies the extra holes. Buying a matching bench dog drilling guide or template can help keep a long row consistent; a carefully made shop jig is also fine if it holds the bit square and repeats the spacing accurately.