Gweike and Finger Joints

[scarn (Jason)]

I wanted to see if anyone out there has had good experience cutting finger joints using a web app like https://www.festi.info/boxes.py/? No matter how many YouTube tutorials I watch, I keep cutting out boxes and no matter the burn correction I use, I cannot find a tight fit.

I watched a few videos and started at a .06 correction, but no matter what I do, none of the sides fit. I am testing using BurnTest - Boxes here creates a few sides to test, no luck.

Anyone else use a different burn correction than .06?

[jkwilborn (Jack Wilborn)]

@scarn

.06 correction

Not sure what this is… kerf?

If it’s kerf, measure it, that will at least get you in the ball park.

I know the kerf of my materials. If you know the kerf, then use 1/2 of that as a starting point.

If you have multiple sides it may be an issue, so kept the kerf consistent… 1/2 on each side.

I’ve used boxes site for a few boxes…

Sometimes I will import them and cut a corner out to ensure they fit snug… this was made with boxes.py…

Cut out with my China Blue 40W.

Good luck

[dkj4linux (David Johnson)]

I use boxes.py as well and always set the burn correction to 0… no correction. Then, in Lightburn, I use a kerf offset of 0.08mm – about 1/2 of 0.167mm (measured, as Jack suggested) – to get nice fitting fingers joints.

– David

[scarn (Jason)]

Great info, looks like I need to do some kerf testing.

Great thoughts! @jkwilborn Yes, looks like I do mean kerf. I was just using the language from the site, but you are correct. @dkj4linux great idea! I like that better, I am never a fan of using data and not knowing where it came from.

I was reading about using a circle inside a box, and messing with kerf there to test. I think ill try that.

[jkwilborn (Jack Wilborn)]

Should have posted this link… sorry about that…

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…

Great tool —> thanks @BillieRuben

[MikeyH (Mike Hembrey)]

Making and reading that Vernier was fun! First one I made had 2 squares go into LaLa Land. Then I had fun with placing them. Then came them popping up when I tried to adjust the slide. I finally used part of the first one to hold them down while I moved the slide. Final result in 2.8mm Baltic ply, 1.3/20 = 0.065 kerf. Not bad in my opinion for the Sculpfun 10w laser.