Bench joinery
Dovetail slope angle
- where
- angle from the reference axis (°)
- slope denominator (1:n)
Explain this equation
Converts a dovetail slope given as a 1:n ratio into an angle, for setting a bevel or marking gauge.
n is the slope denominator. A 1:6 slope moves 1 unit across for every 6 units along. θ is the angle of the tail side measured from the reference line, in degrees.
The ratio defines a right-angled triangle with sides 1 and n. The angle opposite the side of 1 is arctan(1/n).
1:6 is about 9.5°, 1:8 about 7.1° and 1:5 about 11.3°. A bigger n gives a shallower angle.
Watch out: this is only a marking conversion. It does not recommend a slope for any timber.
Convert a rise-to-run slope of 1:n to an angle.
Enter your values to see the result.
Good to know
This is a marking angle, not a recommendation of slope for a timber species or loading.
Sources
- Geometry / arithmetic
This is a calculation aid, not a structural design or compliance certificate. Every default is an example, not a specification for your project.