They say necessity is the mother of invention. Sometimes the necessity is simply avoidance of unpleasant tasks such as cutting down 3500 header pins by hand. [Nixieguy] and his coworkers were faced with 50 prototype boards bearing 70 overly long pins apiece. He saved them from cutting them all down by hand by making a tiny improvised circular saw/grinder.

[Nixieguy] started by laser-cutting a combination tool holder and grinding platform. His laser failed before he could fashion a guard to keep the pin bits out of the motor or cut all the pieces he had in mind. The grinder is made from a 10A brushless RC motor, a motor driver, and a servo tester. [Nixieguy] machined an adapter to connect the disc to the shaft.

The transformer is there to hold the thing down during use since it’s so lightweight. He’s wearing two pairs of gloves because the pin cuttings were hot enough to sear skin. [Nixieguy] is planning on a complete redesign including a motor guard and the ability to adjust the depth. Maybe he can turn it into a chainsaw, maybe not.