I make this project in my garage without fancy tools, but with a cheap drill press and other common tools.
I started with a row material that i have bought in a shop near home.
The materials for this PCB holder are aluminum, except for the threaded bar that is iron.
This PCB holder is similar to a bench clamp, it has one fixed jaw while the other jaw that can slide by rotating the threaded bar.
But the mobile jaw is pushed by the spring and not directly to the threaded bar. In this way, the pressure to hold the PCB is not too much and the PCB does't bend.