Glueless wood notch design ideas for 3d model toys

[j.r]

After seeing this post on making little 3d model pieces from scrapwood, I have been obsessed with making these little pieces as toys for myself and the kiddos in my life!

My issue is this: these pieces (and even the awesome 3d model reindeer model) are (1) really sensitive to the thickness of the wood (I am using 1/8" BB) and (2) over time, with reuse, the fit tends to loosen.

I have tried adding nodes on the inside of the notches. This has helped some, but the two issues above still plague my design. I am considering playing with adding ‘relief’ cuts below the nodes so the wood is bending slightly at the contact points instead of being compressed.

Anyone have any ideas I could try for a reusable, kid-friendly yet secure, notch design that can handle the slight thickness variation I encounter with BB plywood?

[Jules]

Yeah, give “Dan’s Teeth” a try.

Serrated tabs - no more glue

I love design but I don’t much care for assembly. Why should you have to deal with glue when your Glowforge can make the fasteners for you? I did some experimenting with serrated edges on tabs, and the results have been terrific. Proofgrade plywood is very consistent in thickness, so when using it, you can reliably depend on a design with serrated tabs to go together with a few taps from a rubber mallet. I’ve printed a single serrated design from Proofgrade maple, cherry, walnut, and I think…

[evansd2]

@Jules

Dan’s Teeth

Teeth tend to be one way and wear even faster than nodes. That thread is useful though.

If it were me, I’d look into making self-locking tabs that grab. Oh hey, look at that, it was me like 2 years ago.

Simple locking tab joints

I wanted to make a way to lock a structure together that was fairly strong and could be dissembled with no tools. This is an early (very rough) prototype of that effort. [image] [image] I refined the design to use smaller pegs and a more robust rounded center tab in a holiday gift, but the prototype pieces illustrate the concept pretty well. The whole thing was cut out of birch ply. If you attempt something like this beware that hardwoods will break very easily across their grain. Orient a…

But that’s not what you wanted. There’s a writeup of this somewhere. Hang on.

Aha, here we go. I did similar joints to these, you can probably adapt it to work for you since you know your way around nodemaking. I actually did it with nodes that grabbed on both pieces, it was extremely strong. I swear I wrote that up. I’ll have to dig deeper.

From this article:

CNC Panel Joinery Notebook

[evansd2]

Aha! December 2017, seems like a lifetime ago.

Acrylic Honey Bee

There are lots of ways to make self locking notches. I goofed with it a while ago and made these guys: [image] It represents 4 concepts, 1&2 can be backed out but 3 and 4 are fairly permanent. Once you click them together it’s almost impossible to undo 3&4. I took some inspiration from the 50 digital joints project, found here. The cross “x” joint in particular is relevant. Edit: so the nice thing here is that the pieces are identical. 2 #1 pieces will lock together, 2 #2 units, etc. mak…

[j.r]

Whoa… Y E S! This is approach of making notches, with holes to match the nodes, makes so much sense! I am interested in making my pieces easy for a 2yo to put together, so I am going to try adding the relief cuts shown in the Make article so friction won’t be as much of an issue. Thank you for this idea!

[j.r]

Those seem excellent for a model I want to put together once. I worry they wouldn’t work as well for a ‘reuse’ application such as this.