What angle should dovetails be cut at?
1:6 in softwood, 1:8 in hardwood — about 9.5° and 7.1° from square. Why it is marked as a ratio rather than an angle, and what the difference actually buys.
1:6 for softwood (9.5° from square) and 1:8 for hardwood (7.1°).
Over 3/4" of stock, 1:6 moves each tail edge 0.125" sideways and 1:8 moves it 0.094" — about a thirty-second of an inch between them, which is the whole argument.
How that is worked out
- The slope is set as a ratio because that is how it is marked out: one unit across for N along, stepped off with a rule and a square, no protractor involved.
- 1 in 6 is 9.5° from square; 1 in 8 is 7.1°.
- Softwood gets the steeper flare because it compresses and needs more mechanical grip. Hardwood gets the shallower one because the steeper flare leaves fragile short grain at the tail corners, and hardwood's grip is already sufficient.
Slopes in general use, over 3/4" stock
| Slope | Angle from square | Rise / run | Taper per edge | What it suits |
|---|---|---|---|---|
| 1:6 | 9.5° | 1 in 6 | 0.125" | The softwood slope. More flare, more mechanical grip, more short grain at the tail corners. |
| 1:7 | 8.1° | 1 in 7 | 0.107" | The middle. A reasonable default if you do not want to think about it. |
| 1:8 | 7.1° | 1 in 8 | 0.094" | The hardwood slope. Less flare, stronger corners, and the one that looks refined in walnut. |
Worth knowing
- The angle matters far less than cutting consistently to the line. A joint cut carefully at the wrong slope fits; one cut carelessly at the right slope does not.
- Too steep and the tail corners are short grain that breaks off while you are chopping the waste. Too shallow and the joint approaches a finger joint, which relies entirely on glue rather than on any mechanical lock.
- A dovetail marker or a bevel gauge set once, and used for every cut in the job, beats measuring each one. Consistency is what makes the joint close.
- These are the through-dovetail slopes. Half-blind dovetails for a drawer front use the same angles — what changes is that the pins are cut into a socket rather than through the board.
Work out your own numbers
- Dovetail and box joint templates
Set out the joint, print it at true 1:1 scale, and glue the paper straight onto the board.
- Mortise and tenon sizing
Tenon thickness and shoulder by the rule of thirds, and the length a blind or through mortise allows.
Related questions
- What is a 1:6 dovetail angle in degrees?
- About 9.5° from square. The ratio notation survives because it is how the joint is actually marked — measure one unit across and six along the edge of a square, and join the marks. No protractor, and no accumulating error from reading a scale.
- Should I use 1:6 or 1:8 for dovetails?
- 1:6 for softwood, 1:8 for hardwood, and 1:7 if you would rather not think about it. The practical difference is small and mostly aesthetic — 1:8 looks more refined in a dark hardwood, 1:6 looks more emphatic. Both hold fine when cut well.
- Does the dovetail angle affect strength?
- Less than people expect, within this range. Too steep leaves short grain at the tail corners that chips out and weakens the joint; too shallow loses the mechanical lock and leaves the glue doing all the work. Anywhere from 1:5 to 1:9 is sound, and fit matters far more than where in that range you land.