[![Bevel gear combo to transfer hand torque to a pinion to drive a rack](https://i.stack.imgur.com/JMKER.png)](https://i.stack.imgur.com/JMKER.png)

I'm trying to design a little device which is hand-driven and which involves turning a bevel gear pair. I want a small gear pair but I don't want it to be weak. The forces involved will be small (it's attached to a pinion along which will slide a rack < 1 kg), but of course I still need to check the safety factors involved. So here's my question:

Since it's hand-driven, what torque value can I enter for the strength-calculations? I search for "typical torque values human hand" (and variations on this), but I keep receiving maximum human turning strengths which are definitely not going to turn up with this device. The dial has a ~3 cm diameter.