Derek, your point about the thermal properties of metal is a good one.

Kazama, something to consider is that the shape of the knob's "Gripper" section is only engineered to work as a plastic unit. For instance, it expects that there will be a little flexibility to the plastic.

If you cast it in metal with the same shape, it will have different properties, and therefore won't work right. It will either slip off too easy or it will get stuck on so bad that you'll damage the PCB when you try to remove it.

So you'll have to come up with some alternate way of securing it to the shaft. A side-screw sounds like the logical way to go.

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Tony Fabris