[Shashank] has a modest tool collection but is missing a rotary tool. He needed one for a project he was working on but didn’t think that it would get much use after the current project was completed. So instead of buying a rotary tool, he decided to make one to get the job done.
The project started out with a 40mm PVC pipe that would serve a the main body of the tool. Two MDF disks were cut to fit inside the pipe. One was used for mounting an RC vehicle brushless motor and the other was bored out to accept a pair of bearings. The bearings supported a modified pin vise that acts as the chuck for securing rotary tool bits. A 20-amp ESC and a servo tester control the motor’s speed and can get the motor up to 18,000 rpm.
Although this worked for a while, [Shashank] admits it did fall apart after about 20 hours of use. The MDF bearing mounts crumbled, thought to be a result of vibration due to mis-assignment between the motor and pin vise. He suggests using aluminum for the bearing mounts and a flexible coupling to connect the motor to the pin vise. If you’re interested in making your own rotary tool but don’t have any spare motors kicking around, this 3D printed vacuum-powered rotary tool may be for you.