This is a clone of the fantastic PCBite PCB holder.
The original is great as you can even use a hot air gun to do some serious rework.

But I needed a few more for a project, just to hold multiple boards that are wired together.

As a base plate you can use a cheap build plate. I got some at AliExpress.

I printed mine with PLA, so as a holder it is fine, but I don't expect it to hold up with a hot air gun or some serious soldering.

1. What you need is a 30mm long compression spring with an outer diameter of 12mm.
   Made from 0.8mm stainless steel wire. These can be found on AliExpress.
2. A 15mm round, 4mm thick disc magnet with a 4mm countersunk hole.
   Also available on AliExpress.
3. Two M3 x 20mm countersunk screws. One goes into the pin for extra strength, the other one
   is used to screw the magnet in place on the bottom side of the holder.