Quote Originally Posted by Ross77 View Post
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If you are worried about thermal effects then you will definitely need the consider dynamics as well, beam/column frequency and moving masses etc. just adding more mass can lead to resonance not to mention problems with accel/decel....
Hi Ross,
It was the mass/rigidity that convinced me that thermal probles should be addressed. The same mass of aluminium should be more rigid than steel, but has about twice the thermal expansion and also has much better thermal conductivity - hence easier to control the temp of the whole device.
Hidden agendas are, aluminium is also much easier to work with with the equipment that I have and my workshop temperature varies from freezing (4C) to bloody'ot (33C)

on the C1 ballscrews, I keep looking on ebay.
Mike