This is an interactive explainer on constructing tab and slot projects.

When compensating for the kerf on these kind of projects we add or subtract the kerf value on the sections that are likely to be consistent because they are cut by the laser.

On the sections determined by the materialThickness we don't use the kerf value because there will always be some variation on the actual thickness of any given piece of material, so materialThickness is mostly useful for determining the height of the joints but not for affecting the fit.

Kerf compensation on tabs

Half the kerf gets added on each side of the tab, and the tab height is materialThickness.

So in practice the tab is a rectangle with these dimensions (tabWidth + kerf, materialThickness)

Kerf compensation on slots

Half the kerf gets subtracted on each side of the slot, and the slot height is materialThickness.

So in practice the slot is a rectangle with these dimensions (tabWidth - kerf, materialThickness)

Slot and tab

This shows the interaction between the slot and the tab. Kerf value is exaggerated for demonstration purposes.