Serrated tabs - no more glue


#1

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 Draftboard too. Every one went together perfectly.

The trick is taking a little serration (shown here in blue top-left) and adding it to every protrusion. Steps:

  1. Create a tab and a slot that are the same size
  2. Add the serration and its mirror image to both sides of the tab
  3. Align the serration so the gentle slope points towards the direction of insertion, and the midpoint of the serration is on the edge of the tab (see picture top-right)
  4. Use the “union” or similar tool to join it into one single shape
  5. Print and bang together

The serration is 0.033 inches tall, which means it protrudes 0.0165". The kerf should be about 0.008, so imagine the hills smashing down into the valleys to fill up the kerf. It holds very tightly, but can be forced apart with pliers if needed.

Here’s an SVG with the example images.

serrated.zip (1.3 KB)

This was my test design - it shows tab-and-slot, plus some other variations on the technique.

Note that this is my personal project and is not supported by Glowforge. (I do get to do them occasionally :slight_smile: ).


Going box crazy
#2

Another of those things we all knew but didn’t.

Makes so much sense it should not be a 'new ’ thing.
Oh well, thanks for waking me up.


#3

Well that’s a thing. Awesome idea! :grin:


#4

I like learning new things all the time. Thanks!


#5

Very nice. I’ve had good luck using curves to do similar locking, they make slot assembly very strong.

There’s a good writeup on curved node technique here:

https://ponoko.zendesk.com/hc/en-us/articles/220289068-How-to-make-interlocking-wood-designs?mobile_site=true


#6

Thanks for sharing the idea/file!


#7

These are awesome. I’ve begun incorporating them into some of my designs. Thank you.


#8

Just made my first box base using these…fantastic time saver and the assembly was so much easier! Two thumbs way up! :+1::+1:


#9

Thanks for bumping this thread. I’m about to make a box and I completely forgot about this method. Must try.