[Azalin]

harmonic drives have poor torsional stiffness, you won't be able to subject it to any high forces when machining so a cast iron housing might be an overkill.

Hi,
Specs of the HD I have says the torsional stiffness is 14Nm where average torque is 55Nm. That's a little confusing for me.

Do you mean I need to use a softer metal like aluminium instead of cast iron on the housing, so that the housing can absorb the high force and help the gearbox not being damaged?

[ardenum2]

Do you mean I need to use a softer metal like aluminium instead of cast iron on the housing, so that the housing can absorb the high force and help the gearbox not being damaged?

no I mean you might not need the stiffness of cast iron, aluminium is also easier to machine. Iron will do a better job with damping though. do you have a low rpm high torque or high rpm low torque setup?