Torque Wrench Handles from 1.0Nm up to 3.0Nm

Low torques are necessary for many applications, such as carbon parts on mountain bikes or screw connections on electronic and robotic devices. But the usual torque wrenches works reliably only at 4 or 5 Newton meters and above.

Fixed torque handles are available, but always for a high price tag ($100-200). This is why a set of 1/4 "drives with low, fixed torque for self-printing becomes handy. Inspired by a NozzleTorqueDrive from Anders Olsson (I like the design), my parts have a larger diameter with more and thicker fins and the housing is screwed. Through a continuous 1/4 "slot all common inserts can be used and even left-hand crews can be used by placing the insert on the bottom.

The case dimensions are the same for all drives and differ only in the engraved torque values. The screwed cap is also the same for all drives. There is a version with slightly more play if print quality affects the thread. The nut value is 19mm or ¾", very common in most countries. Please do not tighten too much; otherwise, the housing may break!

The rotors receive the different tripping torques by different thicknesses of the fins (main feature) and by different lengths in the vertical axis (fine calibration). In the rest state, there is no pressure on the plastic fins, as a result of which the drives should produce approximately the same resistance over time.

The actuators are designed for normal PETG with 100% infill. If ABS is used, the one number smaller rotor can be used to achieve the same trigger value.

I have printed them in different colors, so I always choose the right part.

Use the 'Torque-Bar' and a simple kitchen scale to test the torque values. See pictures.

Note: I tested the wrench handles with a high-quality 'Stahlwille' torque wrench with calibration certificate, but keep in mind they are self-printed plastic parts: they will never reach the uniformity of professional tools. However, it is usually a question of not exceeding the permitted torque value by several Nm, since we simply have too little feeling in our hands. So often no absolute precision is needed.
A higher value of up to 4Nm (or even 5Nm) would also be conceivable, but then the drive piece would have to be glued in, as otherwise the hexagon in the plastic material would end up with time. We will see...

Enjoy!

Print instructions

Printed in PETG on a Prusa i3 MK2.5

Print in original orientation for best results. I printed all parts in 0.3mm layer height, but of course lower layers will work as well.

EDIT: Some users reported bad thread results in 0.3mm layer, so probably 0.2mm give you better results here.

EDIT 28.01.2022: added two stl files for 2.5Nm as requested.

Happy printing!