Bench joinery
Centred tenon shoulders
- where
- shoulder (mm)
- stock thickness (mm)
- tenon thickness (mm)
Explain this equation
Works out the shoulder depth each side of a centred tenon.
T is the stock thickness and t the specified tenon thickness, both in millimetres. s is the depth of the shoulder cut on each face.
Whatever is not tenon is removed equally from both faces so the tenon sits in the middle. That means half of T − t from each side.
45 mm stock with a 15 mm tenon has 15 mm shoulders each side. Often the tenon is about a third of the stock thickness, which leaves three equal parts.
Watch out: the tenon thickness comes from the joint design. Fit allowances, haunches and length are not worked out here.
Calculate equal shoulders around a specified central tenon.
Enter your values to see the result.
Good to know
Tenon thickness is chosen from the joint design. Fit allowances, haunches, length and strength are not inferred.
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.