Torque-wrench calibration fixture

youmagine

This device is based on A_R_B's torque measuring level. Its purpose is to test any 3d printed torque wrenches and see how accurate they are. I modified A_R_B's original design for two reasons: 1) Since gravity is 9.81 m/s^2, the lever arm needs about 203 mm to get accurate results. 2) A stand with a pivot limits errors from downward force of hand motion (only the actual torque gets to the scale). Since you're calibrating 3d printed torque wrenches, you can't expect perfection. But you can at least have a highly accurate lever so you know how far off the printed tool is. The fixture is meant to be assembled with an M3 bolt and nut. Print the two parts. Then drill out the two holes and loosely attach them with an m3 bolt. The bolt is meant to be a pivot point, so it shouldn't be tight. Then just stick the torque wrench onto the hex-fixture and twist. When the scale reads 500g you have 1 N*m of torque. A_R_B's torque wrenches are available at https://www.thingiverse.com/thing:2613057. His original lever is located at https://www.thingiverse.com/thing:2670493.