This is a three part sanding block, made to be very easy to put together.
Scale as you like, but be wary when scaling down, the bolt may need more clearance.
At 100% scale needs about 19cm of sandpaper.
Recommended settings (best to use PLA+ or PETG)
Main block: 20% infill or more, 0.2mm layer, no supports needed
Bolt: use 40% infill, ideally PETG, 4 wall lines, 0.1mm layer.
Wedge: Use whatever settings
None of the parts require supports.