Cheers Gents. It is true that this won't be used for a long time before the final model is built, it is mostly to check a few ideas out, but it must also perform it's main function. This covers very light loads which is one of the reasons I picked wood(-ish materials). We are talking hand cranking load levels (manual operation), so nothing above what my elbow and wrist cannot move shouldn't happen. Parts will be CNCed and joined using cross dowels, which means edge drilling is needed. Would that be harder / worse to do in ply considering it's layered character?

Good idea about doing tests for press fit, I assumed (maybe foolishly) that 0.1mm less clearance will work in MDF.

Another thing I'm worried about with HDPE is electrostatic charge. This machine will grind stuff and the output will be rather fine, which makes me worried that it will stick to HDPE (plastic in the end) like crazy with no easy way to discharge (can't ground the chassis with plastic).

Regards,
dsc.