I didn't know the stirling was that efficient? That's interesting to note
This maybe a false assumption of mine but, i don't see the stirling...
There is another option to the stirling engine; a lens focused to heat water to generate steam to turn a turbine.
A competent laser operator ought to be able to set the machine to cut clean enough to not require deburring.
Have you considered switching to ceramic bearings? They are temperature stable and do not require lubrication.
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