Using LB with CNC. Router bit offset question

I know that LB is designed for lasers. However, it can control CNC very nicely as well. The question is how to offset the router bit so it cuts on the outside of the line instead of on the line like the laser.

Trying to cut a 2"x2" square. However, it comes out to 1-7/8. Is there a way to set this in LB.

There is Offset Shape… but this is going to be a dead end.

It’s just not what LB is designed to do- there’s better software for making CNC toolpaths.

This is the exact purpose of the ‘kerf’ setting, it’s in Lightburn or anything else that’s machining oriented.

Adjust it to 1/2 the tool diameter.

Is it a 1/4" bit?.. that would slice 1/8" into the cut… giving you your 1-7/8"…


Would it not be the whole diameter of the bit. That way there is not cutting into the shape.

If the red circle is your tool and black line, the tool path as in your artwork, the center of the tool follows the path. As you can see if it’s going up or right, it’s ‘removing’ only 1/2 the tool width (kerf).

Screenshot from 2022-10-08 15-46-30

Only 1/2 of the tool is cutting into the shape. The ‘tool’ follows the tool path… center of the tool follows the path… results in it cutting 1/2 the kerf of the tool into the material.

You need to move the center of the tool ‘out’ by 1/2 it’s width…

Make sense?


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Got it. Thanks.

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