Examples
Examples
Try the starting example
- Board width across joint (mm)
- 60
- Target finger width (mm)
- 10
- Added clearance in each cut slot (mm)
- 0.2
- Even segment count
- 6
- Actual nominal finger width (mm)
- 10
- Cut slot width including clearance (mm)
- 10.2
- Board A cut centres (mm)
- 5, 25, 45
- Board B cut centres (mm)
- 15, 35, 55
Try another scenario
- Board width across joint (mm)
- 80
- Target finger width (mm)
- 20
- Added clearance in each cut slot (mm)
- 0.5
- Even segment count
- 4
- Actual nominal finger width (mm)
- 20
- Cut slot width including clearance (mm)
- 20.5
- Board A cut centres (mm)
- 10, 50
- Board B cut centres (mm)
- 30, 70
Calculation method
Calculation method
Even segment count
Choose the nearest positive even number to board width / target finger width, with at least two segments.
Actual nominal finger width (mm)
Board width / segment count.
Cut slot width including clearance (mm)
Nominal finger width + supplied cut-slot clearance.
Board A cut centres (mm)
Centres of segments numbered 0, 2, 4 and so on, measured from one common edge.
Board B cut centres (mm)
Centres of segments numbered 1, 3, 5 and so on.
Symbols and units
- a
- Board width across joint (mm)
- b
- Target finger width (mm)
- c
- Added clearance in each cut slot (mm)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- Alternating complementary finger/slot centres on two boards sharing a reference edge. Uses an even segment count and adds clearance to slot width only. Tool diameter, endpoint overcut, actual fit and joint strength need separate checks; cut positions are nominal centre coordinates.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
OpenStax: arithmetic and geometry ↗
Background reading; this does not imply endorsement or independent review of SumFizz.