Kerfing issue - same material thickness, same default settings, different outcomes

So, I am having a bit of an issue. I am not sure if it’s user error :rofl:, file error, or a combination.

For my latest Number Five project, aside from the living hinge, I have 2 different types of joints, shown here.

I set this up, tested it, and made my Number Five from proofgrade MDF using the default GF settings. For the most part, everything snapped together very nicely with no issues. But, when I tried to cut the same design from Maple medium weight plywood that is the same thickness as the MDF, the following happened:

A. a lot of the parts were loose and wouldn’t snap together, despite using the recommended settings from GF
B. some of the smaller parts (5-10mm in size) were cut down so much that I had to redraw them and increase the size of either the tabs or the slots.

So, I tried using a box generator to set up a small box with joints similar to mine and printed it on MDF and then on the Maple medium weight plywood. And, I had the same issue! :frowning:

Any suggestions or thoughts? I don’t want to redraw my Number Five project for a different material every time. Not sure what I am doing wrong.

Different materials will definitely react differently - it depends on how easily they cut and how much burns away when they do. The same thickness is only a start. So yes, if you want snap-together pieces you’re going to need to adjust your settings for each material.

That being said - instead of adjusting your design, you should run tests to get the settings that do what you need need. Cut a 1" square of your MDF - and then measure it, see how much you loose - that’s your kerf. Now cut a 1" square of your plywood - measure it - and see what difference you’re talking about.

If the kerf is larger (which sounds like that’s going to be the answer) try increasing the speed or lowering the power on your cut until the kerfs match. You may find that it never does, which would mean adjusting your pattern - but this should be faster.

@evansd2’s test description may help you get an idea of the steps:


Thanks @deirdrebeth for the assist!

They are correct - different materials will definitely react differently. You will need to test it get the settings needed for the different materials.

I’m going to close this thread. Please feel free to start a new one or reach out to us directly at if you need additional assistance.