Free tool · no sign-up · works with any laser
Laser kerf & fit test
Cut one small test from your material, measure it, and get the exact kerf and joint clearance for tight finger joints and slots.
Read your test
After cutting, fill in what you measured and felt. The settings below go straight into the box generator.
1. Kerf from the key
Measure the height of the key body with calipers: from the straight bottom edge to the top edge beside the finger, not including the finger.
2. Best joint fit
Push the long finger of the key into each comb notch. Pick the notch where it goes in with a firm push and does not wobble.
How it works
- Enter the thickness you measured with calipers and download the test.
- Cut it with the speed and power you use for real projects. Blue labels: score at low power, or switch that layer off.
- Measure the key for kerf, then try its finger in the comb notches and the plate slots.
What the parts do
- Key has a long finger that is easy to push in, and a body exactly 24.00 mm high: measure it to get your kerf.
- Comb copies a box finger joint. Labels show the extra clearance of each notch.
- Slot plate shows which slot holds your material, for dividers and cross joints. Test it with the key finger.
FAQ
Why does kerf change?
Kerf depends on the laser, lens, focus, power, speed and material. Test again when you change any of them.
The fit differs on two sides of the comb.
Your laser beam may be slightly oval or the material uneven. Use the value that fits in the direction you cut most joints.
Do I need an account?
No. Everything runs in your browser and nothing you enter is sent anywhere.