2020 Extrusion Kit for Adjustable PCB Holder

This is the kit of pieces to bolt onto a piece of 2020 extrusion to use with Squinn's PCB holder uprights & associated tooling.

Printing recommendations

Print the rail upright to get good top surfaces on the top-top and shoulder-top. Ensure you can print clean 45 degree overhangs.

All of the feet have a solid flat face, put that side on the bed.

Print the key not at all, you don't need it, unless you think you do, in which case good luck, I have not tested it.

Hardware

You will need 2020 series T-nuts and appropriate bolts up to 8mm long. My T-nuts are M5, the hole is sized for M5, it might be a tight fit but this will help prevent the nut from loosening of it's own accord. 

There are holes for 4mm dowel pins in the ends of the rail, these are for alignment, they are not necessary but will help to ensure the uprights can slide cleanly between two sections of rail, which you probably won't ever do since the gap will be in the middle.

Unless you want to have like, 600mm of pcb holding space. I recommend not wanting that. 400mm is more than I need, but 220mm was very tight for my applications

They do help if the rails don't perfectly fill up your extrusion and you don't want extrusion sticking out the ends, the pins can maintain alignment with an excessive gap.

The legs have holes in their feet for a hypothetical bolt-on foot, I don't have any and didn't plan for any. It's a 5mm hole. I used stick-on pads, I primarily would use heavy bolt-on feet to lower the center of gravity and make it more stable. I don't think this will be necessary for me. You can use this hole in any way you desire. One of you is going to use it for gridfinity, I know it.

Assembly

The legs have alignment teeth. I have the vertical wall of the leg on the outside, this is personal preference do what you want cuz a pirate is free.

Put long legs in the back so the stand has better leverage to resist  tipping when you push against places near the top of a big PCB you're working on. You can put long legs in the front, you are a pirate, but as there shouldn't be any forces tipping the stand towards you, this shouldn't be necessary. If you have such forces, post a make, I'm sure you're doing something I'll look at and feel something.

The legs accept 2 bolts, this is not necessary for any PCBs I work on, but may be appropriate if you work with heavier stuff, especially on long legs and in the back. I included both holes for aesthetics

Loosely assemble all of your rails on the extension with their hardware. If you are using alignment pins, make sure they are engaged. Get one rail in position and lightly tighten it's screws. Get the other rail in position, lightly tighten those screws. Slide an upright onto the gap and make sure the alignment is satisfactory (again, you are a pirate), then tighten everything down for good. and assemble the rest of the holder tooling.

Derived dimensions of the dovetail from analyzing the original model.
All these models were made from scratch based on Squinn's design as a spec