Slots and Tabs - need guidance

Just started to try my hand at modeling my own projects, did a clamp hanger over the weekend and the tabs aren’t long enough and the slots weren’t very good either.

I got new up cut bits in the mail yesterday I’m going to switch to to see if those help instead of the compression bit I had. Any advice on how to make them better would be awesome.

Working with 3/4 ply and fusion 360. I can share the fusion file if needed. Trying to learn as much as I can before I start building things that really matter. Thanks!


2 Likes

Noticing a few things here:

  1. Looks like you have one dogbone in the top corner of the slot, but not on the bottom. You’ll need them on all 4 corners. Any inside corner that needs to be square needs one.
  2. You’ll also need dogbones on the tab for the triangle piece.
  3. Not sure if it’s sanding or from the machine, but the cuts look a little wonky, so might want to make sure the Maslow is cutting accurately.

I just went through this process on a design in Fusion, and it helped to add 0.016 - 0.008 clearance where faces meet. For my design, I tried 8 thou on each side where two faces met or 16 thou on a single side.

People recommended a dogbone plugin for Fusion, but I found it easier to just use a drill command and run that first. Change the geometry selection mode to “selected points” then just click the corners you want to dogbone, check your depth settings, and you’re good.

4 Likes

I think overall the cuts looks pretty good. There are some places that look a bit off, but for the most part they look pretty good. As @kyleschoen mentioned, you want the dogbones on all inside corners. Also, I recommend giving a little extra clearance in slots than you need. In my experience, cutting a slot exactly 3/4" for a 3/4" tab usually results in something too tight to fit in. I’ve started giving an extra 1/64" or so on all sides of the slot. That usually results in the tabs going in snuggly without having to cut or sand down the tab in order to get it in the slot.

Be aware that an upcut bit with plywood usually makes a rough edge on the up-facing plywood during the cut. The bit is designed to pull material up and out of the cut, which also pulls up on the top layers of plywood resulting in a rough edge.

2 Likes

Run this one by me again. how best do I check for accuracy? This is the second cut and it did… okay. I was working off to one side instead of the middle though. may’ve caused issues.

I’ll give this a try. I baked the dogbone cuts into my program, but it didn’t execute them all. Also my tabs didn’t work which may’ve caused things to get weird…

Okay, I see. Regarding #3, I didn’t know that you had beveled the corners – they looked rounded like the machine was having trouble. I don’t think you really need those, but might help if the fit is pretty tight.

You’ll want dogbones just like you have them in the drawing, then you’ll want to either make the tabs a little narrower, or the slots a little wider. I think I would use an offset face command on the slots by about 0.008 (ends up being 0.016 or 1/64th total since both sides move outward like @Andith mentioned as well.)

Might have to end up playing with the offset face amount and you should also measure your stock with a caliper to make sure it’s actually the size you think it is!

3 Likes

I got a better cut today on a practice piece, but I need to figure out the drill operation feed rate. It seems I burned the holes.

Thanks for the guidance! Any other tips are appreciated.

*I think the paint caused the Maslow to skip and be sloppy on the cuts. It’s scrap wood though. *


2 Likes

Looks great! How’s the clearance in the slot?

1 Like