Torque measuring lever to measure low torques with a simple balance. 200mm lever gives 500g pressure or weight per newton meter. So well suited to measure torques up to 6Nm with a 3kg scale, so well suited to test my Fixed Torque Wrench Handles (http://www.thingiverse.com/thing:2613057).
13mm (½") as I tested the torque rotors with an M8 screw (with the 'Reduction' part).
Use high infill and strong bondig materials if you need to test more than 3Nm. Tested up to 6Nm with PETG.