Every shop needs a wooden mallet, and it is a better project than it first looks. The head has to be dense enough to transfer a clean blow without bouncing, the handle has to fit the hand and resist splitting, and the joint between them has to tighten rather than loosen with use. A through-tenon locked with a wedge does all three. The wedge spreads the tenon across the grain of the head so that every blow drives the joint tighter. Use beech if you can find it — it is the traditional choice for mallets — but ash and oak work equally well. The mortise here is a round hole drilled with a Forstner bit, which sidesteps the need to cut a precise rectangular mortise and still produces a joint that will outlast the rest of the shop.

A Shop-Made Wooden Mallet

What you need

1 75 x 50mm PAR hardwood (beech, ash, or oak), 200mm length head stock — 150mm used, remainder for waste and end cleanup
1 22mm hardwood dowel, 400mm length handle — ash or beech preferred for grip strength
1 hardwood offcut, approximately 6 x 30 x 60mm for the locking wedge
1 small bottle PVA wood glue
0.1 litre boiled linseed oil handle finish — a very small quantity is needed

Step by step

Cut the head block to 150mm. Check the cut with a try square — any twist means the mallet will tip on every blow. Clean up both faces with a block plane until the block sits without rocking on a flat surface.
15 min
Mark the mortise centre on the top face: centred across the 75mm width, 45mm down from the top end. Scribe clearly with a marking awl so the bit has somewhere to register.
5 min
Clamp the head face-down onto a scrap board with two clamps, one on each side of the layout mark. Fit a 25mm Forstner or spade bit in a cordless drill, set the drill to low speed, and bore straight through the 50mm face. The exit hole will blow out slightly against the scrap board; that is on the inside of the joint and does not affect anything.
15 min
Prepare the tenon. Sand or plane the top 60mm of the dowel until it slides into the mortise with firm hand pressure and no slop. Work in small passes and test repeatedly — remove too much and the joint will be loose. The tenon should need a light tap to fully seat.
15 min
Cut the wedge kerf. Hold the dowel in a vise, tenon uppermost. Draw a line across the centre of the tenon end at 90 degrees to the grain direction of the head. Saw 35mm down this line with a fine-tooth tenon saw, keeping the cut centred.
5 min
Saw the wedge from your offcut: about 6mm wide and 55mm long, tapering from 5mm at the fat end to a point. A few strokes with a block plane or rasp will taper it cleanly. Check it fits into the kerf.
10 min
Push the handle through the mortise from the bottom until the tenon protrudes 20mm above the head's top face. Apply a thin bead of PVA to the wedge, set it in the kerf aligned with the kerf cut, and tap it home with any hammer until it seats firm. Set aside for 30 minutes.
10 min
Saw the protruding wedge end as close as possible to the head's top face, then plane flat. Trim any dowel protruding below the bottom of the head flush as well — a perfectly flush finish here is fine.
10 min
Shape the handle grip. Starting 280mm from the bottom of the head, use a block plane or rasp to flatten the round dowel toward an oval section — four flat passes on the cardinal faces, then four more at 45 degrees. The grip should end up roughly 32mm across and 22mm deep. Hold it as though you are about to strike and adjust until it sits comfortably. Sand the handle through 80, 120, and 180 grit, then wipe on a coat of boiled linseed oil. Let it soak for five minutes and wipe off every trace of the excess.
15 min

Tools for this project

Hanpex Pro Hand Fine Cut Handsaw The size that covers most jobs without being unwieldy.
Powerful Speedy Hand Drill 1/4-Inch Capacity with 13Pcs Drill Bit Set Worth paying for — the budget versions flex under load.
Cordless Torque Electric Screwdriver Projects Cheap, and does the one thing it needs to do well.
Adjustable Universal Precision Hand Plane Sometimes traditional tools are the best

Afterwards

Leave the assembly for 24 hours before shaping the handle — the PVA needs to cure before the joint is stressed. After oiling, lay oily rags flat outdoors or submerge them in a bucket of water before disposal: bunched boiled linseed oil rags can self-ignite. Allow 48 hours for the oil to oxidise before the mallet goes into regular use. Check the wedge every six months — a head that rattles needs a further tap with a hammer. Store the mallet lying on its side or hanging, not balanced on the handle end.

Questions

Can I use pine instead of hardwood?

Pine makes a lighter mallet that works well for driving joints in softwood or for general assembly work. The head will dent faster and will not hold up to heavy mortising. For occasional use it is perfectly serviceable and easier to find in short off-cuts.

My hole is too wide and the tenon rattles. Can I rescue it?

Wrap the tenon end in one or two layers of thin veneer tape or brown kraft paper, then apply the wedge as normal. This takes up a small amount of slop without affecting the joint's strength. If the gap is more than 2mm all round, the joint will not hold reliably and it is worth starting the head over with fresh stock.

Why does the wedge kerf have to run across the grain of the head?

The wedge spreads the tenon in the direction of the kerf. Across the grain of the head, that spread is absorbed without risk of splitting. If the kerf runs with the grain, the wedge forces the tenon to split the head along its weakest line. Check the head grain direction before you saw.

Does the head need finishing?

Leave it bare or sand the striking faces to 180 grit. A film finish makes the striking face slippery and peels off with use. Oil only the handle — it is the only part that needs protection from hand moisture.