How to Cut a Through Mortise and Tenon Joint
A Through Mortise and Tenon Joint in English oak and African Mahogany.
Start with the Tenon
Saw the tenon cheeks and shoulders first because it is easier to size a mortise off a tenon than vice versa.
Fig 1
Tidy the Tenon Corners
Pare inside the angle between the shoulders and cheeks with a skew chisel.
Fig 2
Using the Corner Chisel
Use the corner chisel with its back against a tri-square blade to impress the mortise corners.
Fig 3
Using the Mortice Chisel
A sequence of chops across the grain removes the waste to a few millimetres depth as a series of chipping. Use the widest mortise chisel that fits between the lines.
Fig 4
Tidy Up the Mortice Corners
Use a corner chisel to square up the socket ends and remove chippings there, then repeat the series of chops with a mortise chisel.
Fig 5
Repeat on the Opposite Side
Do not chop right through, as the far side would split. Instead, turn the wood over and repeat from the other side. Work accurately enough and they will meet perfectly in the middle – Channel Tunnel style!
Fig 6
Using the Bevel Edged Chisel
Clean the mortise ends and sides by paring with the widest bevel-edge chisel that fits.
Fig 7
Pare for a Splinter-Free Fit
Pare the tenon end with a skew chisel to ease insertion into the mortise and prevent it splintering.
Fig 8
Fit the Joint Together
Trial fit the tenon through the mortise, it should be slightly firm but not tight. Either glue, pegs or wedges can be used to hold it in place.
Fig 9
Tools Used for this Project
CH/S-12L Left Hand Skew Chisel 12 mm
CH/S-12R Right Hand Skew Chisel 12 mm
CH/C-10 Corner Chisel 10 mm
CH/B-12 Bevel Edge Chisel 12 mm
CH/M-12 mortice Chisel 12 mm
PAX-TEN/10 Pax 10" Tenon Saw 15 TPI
