Problem with gaps between fingers

[Alcan (Tomas)]

Hi everyone, I know this is probably addressed quite often here, I asked myself, but I still have a problem with the finger width setting and I keep getting a gap there. I’ll describe how I do it.

1. I design a box via boxes.py (picture 1). I measure the exact thickness of the plywood and set kerf to 0.
2. In Lightburn I set the kerf to 0.050 according to my previous tests.
3. And the result can be seen in the last picture.

What am I doing differently that it doesn’t fit exactly?

2)

3)

[ednisley]

@Alcan

What am I doing differently that it doesn’t fit exactly?

The burn setting in boxes.py tweaks the size of all the pieces to make the answer come out right, so that you do not need a kerf adjustment in LightBurn.

I set burn to 0.04 and get close fits in plywood and MDF without further adjustments. Finding the proper value for your hardware will require a few tests, but nothing out of the ordinary.

[jkwilborn (Jack Wilborn)]

I generate them with no application of kerf in the application and apply it in Lightburn.

This way I’m not adjusting it, then overriding the adjustment to correct it…

Did you figure out your kerf? A good value is 1/2 the kerf.

Kerf Offset test: with built-in vernier scale for accuracy, no tools required!

There has been a bit of a flurry of marquetry lately on the forum, and it prompted me to make a tool to help calculate kerf offset accurately and easily, while using minimal material: [image] I was inspired by @jkwilborn’s tool, but I added a vernier scale to make it easier to measure, without needing calipers! Just cut it, slide it, and calculate your kerf. [Preview of the kerf offset tool in LightBurn.] Here’s the file: Kerf Test with Vernier Scale.lbrn2 (2.4 MB) I’d love any feedbac…

Good luck