Joinery Reference
Every joint on this site is described the same way: what it is, where its strength actually comes from mechanically, what it costs in bench time, the cut sequence, and — the part most joinery references skip entirely — the real proportions and numbers behind it. This page explains how to read those numbers across the whole set; the individual joint pages are where the specific figures for a given joint live.
Two genuinely different sources of strength
Every joint on this site resists the loads it faces through one of two mechanisms, or some mix of both, and knowing which one a joint relies on tells you more about how it will actually fail than its name does.
Mechanical interlock joints — dovetails, box joints, most housed or through joints — resist a pulling load through their shape alone. A well-cut through dovetail holds a drawer front on even with no glue at all, because the tail's geometry physically prevents the joint from pulling straight apart; the glue in a mechanically interlocked joint is there for rigidity and to resist racking, not to do the primary work of holding the pieces together.
Adhesive-dependent joints — a plain miter, a butt joint, most lap joints — rely almost entirely on glue-surface area and glue-line strength, because the joint's geometry does little or nothing to resist a load trying to pull the pieces apart along the grain. This is exactly why a mitered corner needs reinforcement (splines, keys, a loose tenon) on anything that will see real stress, while an equivalent dovetailed corner often doesn't.
Mortise-and-tenon joints and their relatives sit deliberately between the two: the tenon's shoulders and cheeks provide real mechanical resistance to racking and some pulling loads, and the glue on the cheeks adds shear strength along a generous surface area — which is the combination that makes the joint family the backbone of frame-and-panel furniture generally, from a basic through mortise and tenon up through drawbored and wedged variants that add a third, purely mechanical layer of security on top of both.
Reading the numbers a joint page actually reports
Dovetail slope, expressed as a ratio (1:6, 1:8) and as the equivalent angle in degrees, describes how steeply the tail's sides lean. A shallower ratio like 1:8 (about 7.13°) is the traditional choice for softer, more forgiving woods, where a steep slope risks splitting a thin pin; a steeper ratio like 1:6 (about 9.46°) is more common in hardwood, where the material can take the more aggressive interlock without the same splitting risk and the steeper angle adds real mechanical resistance to being pulled apart. Neither ratio is universally "correct" — the choice trades holding power against the risk of a short-grain failure in the pins, and that trade moves with the species being cut.
Glue-surface area matters most for the adhesive-dependent joints described above — a lap joint or a loose-tenon joint's real strength scales close to linearly with how much long-grain-to-long-grain contact the glue actually has to work with, which is why widening a lap or lengthening a loose tenon is a straightforward way to add real strength to a joint that has no mechanical interlock to fall back on.
Tenon proportions — thickness as a fraction of the stock, shoulder depth, haunch size where one is used — follow rule-of-thumb ranges that balance two competing failures: too thin a tenon and it shears under load; too thick and the mortise wall around it is too thin to resist splitting. The specific proportions on each joint's page reflect that balance for the joint in question, not an arbitrary tradition.
Movement allowance shows up on any joint that has to hold a wide panel or a board that will genuinely change size across the seasons — a breadboard end's elongated screw holes, a frame-and-panel groove sized to swallow a floating panel's full range of motion. This is the one number on a joinery page that comes directly from the species and width in question rather than from the joint's geometry alone, and it's worth running through the wood movement calculator for your actual project rather than trusting a generic "leave a gap" instruction — see wood movement will destroy your build for why a vague allowance is exactly how a rigidly built panel splits.
What "bench time" actually reflects
The bench-time notes on each joint page describe realistic hand-cut or router-jig time for someone reasonably practiced with the method, not a beginner's first attempt or a production shop's jigged-up repeat-cut time — both of which would badly mislead in opposite directions. A through dovetail cut freehand with a saw and chisels is a genuinely different time investment than the same joint cut on a router jig, and a joint page's bench-time note is describing the traditional hand-tool version unless it says otherwise, since that's the version most readers are actually deciding whether to attempt.
Why so many variants of the same basic idea exist
It's tempting to see a through mortise and tenon, a blind mortise and tenon, a haunched mortise and tenon, a wedged through tenon, and a drawbored mortise and tenon as five names for one joint, but each variant is answering a specific weakness in the plain version. A blind tenon trades the through version's visible end-grain wedge lock for a cleaner appearance, at the cost of that extra mechanical security. A haunch adds a small tongue specifically to resist twisting in a wide rail where a plain tenon's narrow cheek wouldn't. A wedged through tenon splays the tenon's end inside the mortise on assembly, converting a joint that could otherwise be pulled back out into one that mechanically can't be, without adding any metal fastener. A drawbored tenon offsets the peg holes in the tenon and the mortise cheek slightly, so driving the peg physically pulls the shoulder tight — a genuinely different mechanism from clamping pressure, and one that keeps working even if the glue eventually fails, which is why genuinely old furniture assembled this way is still standing. The same pattern repeats across the dovetail family: a through dovetail versus a half-blind dovetail is the same fundamental interlock with the visible-end-grain tradeoff solved differently, and a sliding dovetail adapts the same wedge-shaped interlock to a joint that has to be assembled by sliding rather than dropped straight together, which is exactly the joint a shelf housed into a case side actually needs.
A common mistake: choosing a joint by tradition instead of by load
The single most avoidable joinery mistake this reference exists to prevent is picking a joint because "that's what this kind of piece is supposed to use," without checking whether the actual load matches the tradition. Dovetails on a drawer front make sense because of the specific, repeated outward-pulling load a drawer front takes — but a dovetailed corner on a case that will never see that load is spending bench time on mechanical security the piece doesn't need, when a simpler joint would hold the same load just as well and leave more time for the parts of the build that actually show. The reverse mistake is just as real: a butt-jointed or pocket-screwed corner on a piece that will genuinely be racked and pulled repeatedly is under-built regardless of how clean the screws look, because the joint was chosen for speed rather than for the load it has to survive. Reading the "where its strength actually comes from" section on a joint's own page against the honest demands of the piece you're building is what turns joint selection from a style choice into an engineering one.
Choosing a joint for what the piece actually has to survive
The honest starting question for picking a joint isn't "which is strongest" in the abstract — it's what load the specific application puts on it and in what direction. A drawer front pulled outward hundreds of times over years wants genuine mechanical interlock, which is why dovetails remain the standard there long after glue technology made a butt-jointed, glued drawer front technically possible. A face frame under almost no racking load can get away with pocket screws or a simple lap, because the load it actually sees in service is modest compared to what a drawer front takes. A wide panel captured in a frame needs the joint to accommodate real seasonal movement, which rules out anything that glues the panel rigidly along its whole width regardless of how strong that glue joint would otherwise be. Matching the joint to the load — not to habit, and not to whichever joint looks most impressive — is the actual skill; the numbers on each page exist to make that match a calculation instead of a guess.
Browse the joints below, or start from the through dovetail if you're comparing a mechanical-interlock joint directly against a glue-dependent alternative like a plain miter. If the piece in question has a wide panel or a board that will move with the seasons, read a joint's movement-allowance figure before its bench-time figure — the strongest joint in the world still fails if it was never given anywhere for the wood to go.
Through Dovetail — What It Is, Where the Strength Comes From, and the Numbers
A through dovetail resists being pulled apart because its flared tails have to crush or shear wood to separate — wedging, not glue, does most of the holding.
Half Blind Dovetail — What It Is, Where the Strength Comes From, and the Numbers
A half-blind dovetail's pins stop around three-eighths of the stock's thickness, leaving the drawer front's outer face solid while the interlock works.
Sliding Dovetail — What It Is, Where the Strength Comes From, and the Numbers
A sliding dovetail is built for one job only — resisting a shelf pulling back out of its housing — not the multi-directional racking a corner dovetail handles.
Secret Mitered Dovetail — What It Is, Where the Strength Comes From, and the Numbers
A secret mitered dovetail hides a full dovetail's interlock behind an eighth-inch lap of miter on typical three-quarter stock — same strength, invisible on it.
Dovetail Key — What It Is, Where the Strength Comes From, and the Numbers
A dovetail key isn't structural at all — it's an inlaid repair pulling a crack's two sides together, cut steeper than any joinery dovetail's flare ever is.
Through Mortise And Tenon — What It Is, Where the Strength Comes From, and the Numbers
A through tenon's two cheeks glued flat against the mortise walls are the strongest glue geometry in wood joinery — and the exposed end can still be wedged.
Blind Mortise And Tenon — What It Is, Where the Strength Comes From, and the Numbers
A blind tenon trades a bit of cheek glue area for a clean show face — on a 1.75-inch leg, a typical tenon gives up roughly a third of a through tenon's area.
Haunched Mortise And Tenon — What It Is, Where the Strength Comes From, and the Numbers
A haunch fills the panel groove a top rail's tenon would otherwise open into, replacing wood that a plain blind tenon there would leave dangerously thin.
Wedged Through Tenon — What It Is, Where the Strength Comes From, and the Numbers
Once the wedges seat, a wedged tenon's end is physically wider than the mortise opening — it now has to fail mechanically even if the glue lets go first.
Drawbored Mortise And Tenon — What It Is, Where the Strength Comes From, and the Numbers
A drawbored tenon needs no clamps at all — an offset peg hole, typically a sixteenth to three-thirty-seconds of an inch, does the clamping permanently.
Loose Tenon Joint — What It Is, Where the Strength Comes From, and the Numbers
A loose tenon's two mortises can go anywhere convenient at any angle, since nothing ties the tenon's length or position to either board's own grown end.
Domino Joint — What It Is, Where the Strength Comes From, and the Numbers
A Domino joint has no single fixed strength figure — stacking two smaller mortises side by side beats upsizing to one larger cutter, cheek area for cheek area.
Box Joint — What It Is, Where the Strength Comes From, and the Numbers
Straight box-joint fingers give up a dovetail's mechanical wedging entirely, but the glue area they trade it for still runs close to double a plain miter's.
Bridle Joint — What It Is, Where the Strength Comes From, and the Numbers
An open mortise glues to its tenon with the same cheek area a closed mortise gets, but resists racking less — confinement, not glue area, is what changes.
Half Lap Joint — What It Is, Where the Strength Comes From, and the Numbers
A half-lap's flat overlap gives roughly four times a butt joint's glue area, but nothing physically blocks the pieces sliding apart if that bond ever lets go.
Cross Lap Joint — What It Is, Where the Strength Comes From, and the Numbers
A cross-lap sitting mid-span has no forgiving edge to hide an error — a shallow notch on either side leaves the whole assembly rocking rather than lying flat.
Edge Lap Joint — What It Is, Where the Strength Comes From, and the Numbers
Standing boards on edge for an edge-lap changes what the joint resists — it's fighting bending, not the pull-apart force a face-cut half-lap deals with.
Mitered Half Lap Joint — What It Is, Where the Strength Comes From, and the Numbers
A mitered half-lap looks from outside like a plain miter, but the hidden overlap underneath carries a straight half-lap's own glue area, not a miter's.
Rabbet Joint — What It Is, Where the Strength Comes From, and the Numbers
A rabbet adds a second glue face at ninety degrees to the first and physically registers the mating piece sideways, which a flat butt joint can never do.
Dado Joint — What It Is, Where the Strength Comes From, and the Numbers
A dado still carries real weight with no glue at all — the shelf simply bears on the channel's shoulder, the same way a ledge holds up anything set on it.
Stopped Dado Joint — What It Is, Where the Strength Comes From, and the Numbers
A router-cut stopped dado leaves a rounded end no square-cornered saw kerf ever would, which then has to be squared by chisel or matched by notching the shelf.
Dado And Rabbet Joint — What It Is, Where the Strength Comes From, and the Numbers
Adding a rabbet to a shelf's end lets it register against both the dado's floor and its wall at once, which a plain dado on its own simply cannot manage.
Housed Joint — What It Is, Where the Strength Comes From, and the Numbers
"Housed joint" is the older, broader term a shelf dado sits inside of — it also covers a stair stringer housed to seat a tread, which "dado" never really did.
Shiplap Joint — What It Is, Where the Strength Comes From, and the Numbers
Shiplap boards are left deliberately unglued so each one can move on its own — a 5.5-inch pine board can grow a tenth of an inch across a real seasonal swing.
Biscuit Joint — What It Is, Where the Strength Comes From, and the Numbers
Despite its name, a biscuit's real job on most glue-ups is keeping boards aligned as clamps tighten — the edge joint underneath is already strong without it.
Pocket Hole Joint — What It Is, Where the Strength Comes From, and the Numbers
A pocket-hole joint has no glue-area math at all — the entire strength case is the screw itself, and getting its length right matters more than anything else.
Dowel Joint — What It Is, Where the Strength Comes From, and the Numbers
A dowel joint's glue area looks respectable on paper, but a dowel resists shear across its own narrow cross-section, and is more likely to shear than unglue.
Spline Joint — What It Is, Where the Strength Comes From, and the Numbers
A spline only strengthens a joint if its own grain runs across the joint line — the same strip cut the other way is just end grain glued into two grooves.
Knock Down Fastener Joint — What It Is, Where the Strength Comes From, and the Numbers
A cam-lock fastener clamps two pieces with real mechanical force and zero glue, built to come apart and go back together — its tolerance is the tightest here.
Miter Joint — What It Is, Where the Strength Comes From, and the Numbers
A plain glued miter is the weakest joint on this site, because both mating faces are end grain — the single worst glue geometry wood joinery has to offer.
Splined Miter Joint — What It Is, Where the Strength Comes From, and the Numbers
A splined miter's spline crosses the joint line to convert weak end-grain glue into real shear strength, sized to about sixty to eighty percent of the diagonal.
Keyed Miter Joint — What It Is, Where the Strength Comes From, and the Numbers
A keyed miter's slots get cut only after the corner is already glued and set — reinforcement added later, unlike a splined miter's groove cut during assembly.
Lock Miter Joint — What It Is, Where the Strength Comes From, and the Numbers
A lock-miter profile self-aligns as clamp pressure seats it, but the setup is notoriously fussy — a few thousandths off and the faces still won't sit flush.
Scarf Joint — What It Is, Where the Strength Comes From, and the Numbers
A scarf joint trades a butt joint's near-zero end-grain strength for long-grain surface by cutting on a shallow angle — structural scarves run as low as 1:12.
Breadboard End — What It Is, Where the Strength Comes From, and the Numbers
A breadboard cap and the panel it caps move at right angles to each other — a 30-inch walnut top can shift half an inch while the cap itself barely moves.
Tongue And Groove Joint — What It Is, Where the Strength Comes From, and the Numbers
A tongue-and-groove joint keeps boards aligned while leaving them free to slide — the tongue stays unglued in its groove so each board can move on its own.
Cope And Stick Joint — What It Is, Where the Strength Comes From, and the Numbers
The cope cut is the hard half of this joint — tracing a profile across end grain rather than with the grain — which is why the bits ship as matched pairs.
Rule Joint — What It Is, Where the Strength Comes From, and the Numbers
A rule joint's cove-and-round profile has to match the hinge pin's distance to the wood surface, or the leaf either binds or opens a gap somewhere in its swing.
Finger Jointed Stock — What It Is, Where the Strength Comes From, and the Numbers
Finger-jointed stock shares a name with the box joint but not a job — it splices boards end-to-end for length, not corners for a drawer front or a box.
Birdsmouth Joint — What It Is, Where the Strength Comes From, and the Numbers
A birdsmouth carries roof load through bearing alone, no glue involved anywhere — the seat cut and heel cut are both set entirely by the roof's own pitch.