A client asked for a wall cabinet in the Shaker manner — quartersawn oak, frame-and-panel door, nothing on it that does not need to be there. I decided to keep a diary of the build rather than write it up after the fact, so this post grew as the cabinet did.
Week one — stock and carcase
Picked through the oak stack for straight, quiet grain and let the boards acclimatise in the shop for a week before touching them. The carcase is dovetailed at the corners — half-blind at the top so the joinery stays out of sight line — and the back is a run of shiplapped boards, left loose to move.
Week two — the door
Mortise-and-tenon frame, raised panel planed to a whisper at the edges so it floats in its grooves. The panel came off the smoothing plane so cleanly I nearly skipped sanding altogether. Shaker doors live or die by their proportions; I sized the rails on the golden-ish ratio the old Mount Lebanon pieces use and it settled the whole composition.
Week three — fitting and finish
Hung the door on unswaged brass butts, planed the meeting stile to a two-coin gap, and turned a small cherry knob for contrast. Finish is two coats of hard wax oil, buffed between coats — oak drinks the first coat and shows its ray fleck on the second.
Delivered on a grey Tuesday and screwed to the wall through the French cleat. The client stood back, said nothing for a while, and then just nodded. That is about the best review a Shaker piece can get.
This is the long version of the dovetail class we run four times a year, written down so people have something to take home. It assumes you can sharpen a chisel and saw to a line. If you cannot yet do either, those are the two things worth practising before you cut a single tail.
Marking gauge set once, used on every piece. This is where accuracy is won or lost.
Stock preparation
Four faces flat, square and the same thickness. There is no recovering from stock that is out, because the shoulder line is referenced from the face and the baseline from the thickness. Ten minutes with a plane here saves an hour of fitting later, and it is the step everybody wants to skip.
Mark the faces and edges before you do anything else. Every subsequent measurement comes off the face side, and once the pieces are in a pile you will not be able to tell which was which.
Setting the gauge
Set the marking gauge to the thickness of the mating piece and do not touch it again until the joint is done. Gauge the baseline on both faces and both edges of every piece, tails and pins alike. A joint where the baselines disagree by half a millimetre will show a gap on one face no matter how well you saw.
Some people set the gauge a hair proud so the joint stands slightly above the surface and is planed flush afterwards. We do this on anything that will be finished with oil, and not on anything that will be painted.
Angle and spacing
The angle matters less than people think, and the spacing matters more. A 1:6 slope in softwood and 1:8 in hardwood is the usual advice and it is fine advice, but a joint cut at a consistent 1:7 in everything will look better than one where the slope wanders.
Board width
Tails
Half pins
Up to 100mm
2
2
100–180mm
3
2
180–260mm
4
2
Over 260mm
5 or more
2
A starting point, not a rule. Wider tails read as handmade; narrow pins read as fine work.
Sawing
Tails first. Saw on the waste side of the line, leaving the line itself intact — you should be able to read it afterwards. Keep the saw plate vertical in one plane and let the slope come from the angle you have marked; trying to control both at once is what produces the wandering cut.
Start the cut on the far corner and drop the handle as the kerf establishes.
Watch the line on the face, not the saw.
Stop at the baseline. Sawing past it is not recoverable and shows as a visible overcut inside the joint.
Cut every tail on every piece before you change tools. Repetition is what makes them consistent.
Chopping the waste
Fret saw out the bulk if you have one, then pare down to the baseline. Work from both faces and meet in the middle — chopping right through from one side blows out the far face every time. Undercut very slightly so the middle of the socket is lower than the edges; nobody sees the middle, and the joint closes cleanly.
Fit is decided at the marking gauge. Everything after that is just carefully not making it worse.
Transferring and fitting
Stand the tail board on the pin board, line up the baseline exactly, and knife around the tails. A pencil is two tenths of a millimetre of slop you do not need. Saw the pins on the waste side of the knife line and the joint will go together off the saw with a mallet tap.
If it will not close, do not force it. Find the tight spot with a piece of paper and pare that one place. A dovetail is only ever tight in one or two spots; taking a shaving off the whole joint to fix one of them is how a tight joint becomes a loose one.
Glue-up
Dry fit fully, then take it apart and lay out everything you need before you open the glue. Hide glue if you want a long open time and a joint you can take apart in thirty years; PVA if you want it done. Glue the pins, not the tails, and only the side walls — end grain drinks glue and gives nothing back.
If the dovetail is the joint people photograph, the mortise and tenon is the joint that holds the furniture up. Almost every chair, table and door in the workshop depends on one. It is also far more forgiving than it looks, which is why we teach it first.
A haunched tenon for a table apron, dry fitted before the shoulders are trimmed.
Proportions
The old rule is one third: a tenon one third the thickness of the stock, centred. It survives because it works — a third leaves enough cheek on either side of the mortise that the walls do not split, and enough meat in the tenon that it does not shear.
In practice you round to the nearest chisel. A 21mm leg with a 7mm tenon is arithmetically correct and annoying to cut; a 6mm tenon chopped with a 6mm mortise chisel is very slightly weaker and takes half the time. Take the chisel.
Mortise first
Always cut the mortise first and fit the tenon to it. A mortise is a hole with fixed walls and there is very little you can do to adjust it after the fact. A tenon is four surfaces you can pare. Working the other way round means adjusting the thing that cannot be adjusted.
Gauge both walls from the face side, so any error in thickness lands on the back.
Chop from the middle outwards, working back towards each end.
Stop about 2mm short of the ends until the depth is right, then pare to the line.
Clear the chips often. Levering against a packed mortise is how you bruise the top edge.
Cutting the tenon
Shoulders define the look, cheeks define the fit. Cut the shoulders with a knife line and a fine backsaw, and take your time — a shoulder that is not square shows as a gap on the outside of the finished piece, where everyone will see it. The cheeks can be rough; nobody sees them and glue does not mind.
Aim for a fit that goes home with firm hand pressure. If you need a mallet, it is too tight, and driving a tight tenon into a mortise splits the leg — often days later, after the glue has dried and the piece is finished.
Haunches and wedges
A haunch is the small step left at the top of a tenon where it meets the end of a leg. It stops the rail twisting and it fills the groove if the piece is grooved for a panel. It costs one extra saw cut and it is almost always worth it.
Wedges go across the grain of the mortised piece, never with it, and they want kerfs cut before assembly. Two thin wedges beat one thick one. Cut them from the same board as the tenon so they move together and the colour matches.
A joint that needs a mallet to close will need a clamp to stay closed, and a repair to stay together.
Common failures
Nearly every failed mortise and tenon we see in repair work failed for one of three reasons: the joint was too tight and split the leg, the shoulders were not square so only half the joint was ever in contact, or it was glued in end grain and never had a chance. None of those is a skill problem. They are all a patience problem.
