Sanding block, for 1/4 of 3M sheet

thingiverse

You'll find plenty of other sanding blocks on Thingiverse. Unfortunately, I didn't find one that I liked 100% so I took all the inspiration I could get (thank you, fellow Thingversers) and modeled my own version. These were my requirements: - Feel good in hand (= fillets, fillets, and more fillets) - Fit exactly 1/4 of a 3M 9x11 sand paper sheet - Have two different profiles, with one for sanding 90deg inside corners So this is what I came up with. I find it is relatively easy to fasten the strip of sandpaper and the sanding block holds it properly in place while sanding. The screws have tapered ends to make it easier to start threading them in. I've used the block on a 15 minutes sanding job, and it still felt comfortable to grip after that time. I have some ideas on improving it but don't have the time right now to experiment. For one, loading the strip of sandpaper and getting a tight fit is a bit cumbersome due to the two loose ends. Also, having two screws to tighten is one too many. There are other, wedge-shaped designs on Thingiverse that only have one screw, and they seem to pull the sandpaper tight while tightening the screw. I'd like to incorporate those principles into this design, probably print one of those designs to study it but again, no time right now. In the meantime I hope you will find this design useful. A few final notes: - Top and bottom should be printed with the orientation in the STL. The screw you will need to flip by 180 and print on its head. On my Mini+ I don't need to print any supports for the short overhangs. Just sand the few rough spots that may occur after printing completes. - I printed mine with 0.2mm layer height. I think the top would have come out nicer and smoother with 0.1mm layer height (I was too stingy to allow for the extra 1.5h it would have taken). - After taking the bottom piece off the printer bed, I noticed the bottom wasn't 100% flat but instead it was a bit concave. If that happens to your print, you can either try to carefully sand it flat (take care not to heat the plastic up too much through sanding), or insert a bit of folded paper (or something else 0.5-1mm thick) in the center between top and bottom and the two screws. That will cause the two screws to pull the bottom piece close and "de-concave" it for a proper, flat sanding surface.