I made a mop useing 150 grit sandpaper. I use it on my benchtop drill press, next to the slowest speed. when I sand puzzzles I use my mouse , and then the sanding mop. on the part that you showed I am very carefull when sanding with the mop. no on it getting away from you it happens but I have a sheet of cardboard sert up so The part will hit the Cardboard.. I haven't broke a part since. blut with me saying that my next one will probably be broke, and that is part of the business but not on a regular basis. Ive used this ;mop for the past 3 years and it still looks good.
IKE