I found this awesome PCB holder but sadly it used imperial standards so I decided to make it metric as well as making some minor improvements to the base to save some material. You will need to print two bases, four of the small knobs, one large knob with and one without indents as well as two grips (you will need to pause the print and insert nyloc-nuts into those).

In addition to the printed parts you will need the following hardware:

• 4 M6*40mm screws (if you go a bit shorter you might be able to stick the screw into the knob instead of the nut for a nicer look)
• 1 M6*80mm screw (to go into the large knob without the detents)
• 1 M6*60mm screw (to go into the large knob with the detents)
• 4 regular M6 nuts (to go into the small knobs holding the rods in place)
• 2 M6 nyloc-nuts (to place into the grippers halfway through the print)
• 2 11.5mm metal rods with about 40cm length each (I cut down a 1m aluminum rod; they can be longer or shorter of course which will determine how big of a PCB you can hold)
• 1 metal spring ~45mm in length with an inner diameter of ~9mm (to go onto the knob with the longer screw)
• 1 metal spring ~15mm in length with an inner diameter of ~9mm (to go onto the knob with the shorter screw; I bought two 45mm springs and cut one down)

You wanna make sure to play with tightening the two grips onto their screws so that when a PCB is inserted you can easily rotate the knob with the detents without it being so loose that it won't lock in anymore.

If you want to change the screw- or rod-size or make changes to the design you can find an OnShape document with everything here. I tried to make everything as parametric as possible while keeping the general shape and size of the original pieces. To get the large knobs with or without the detents you just need to suppress or unsuppress the extrusion on the knob labeled as such.