Inspired by pneumatic disc grinders, this DIY project uses a 755 motor paired with an adjustable power supply to drive a circular sanding disc. A fan blade on the back of the disc helps suck and blow away some of the dust into a lower drawer, which can be filled with a little water.

Components: a 755 motor (D-axis diameter 5 mm, flat section 1.5 mm), an adjustable voltage power supply (3–24 V/3 A) with alligator clips, a 4-inch (100 mm diameter) circular sanding disc, two M4 flat-head screws, four M4 self-tapping flat-head screws, and four M3 self-tapping screws.

In actual use, grinding is very fast; however, it’s easy to accidentally grind beyond the intended dimensions. The choice of printing material and infill density should be adjusted based on your specific needs to prevent cracking when installing the self-tapping screws. The adjustable power-supply cables are routed on both sides, but the other end may press against the housing, so drilling additional holes or pre-drilling existing ones could make assembly easier.