In a YouTube short, I mentioned my preferred method for joining Gridfinity base plates was to solder them together.
Part of that video showed me using this jig:
Since publishing the video, I've had many requests for the model. You can download it by clicking the button above.
However, before you do, here is a quick break down on how I approach the problem. Perhaps this can help if you'd like to make a version customised to your needs.
Keep in mind we want to make a jig which will align a base plate. This is exactly what the bottom of the bins are designed to do. But, for our needs, it's just upside down.
First, I started with a 2x2 gridfinity bin:
I used Fusion 360 with the GridfinityGenerator plugin, but you can absolutely do this within your slicer.
At this stage, I was still experimenting. If you are following along, consider disabling the lip for stackability and adjusting the height.
I didn't do any of that, and had to chop off the bin part:
We're almost done already!
All that remains is to create a hole where we will be soldering:
And, that's it!
I happened to use Fusion 360 but, as you'll see, you can easily do this within a slicer using some cuts and primitive objects.
This was just a hacky project to suit a need at the time. It may actually be one of the worst possible versions of a soldering jig. I didn't even bother removing the holes for magnets.
I challenge you to improve upon the design and, if you do, please show me your version!