DrH - thanks for that, was just curious if u had gone for something other than 6061. makes sense to stick with it. i was going to ask about the bearing supports/recesses, it all sounds like good stuff!

im guessing that u will have a better idea of cost after u have done the first prototypes?

just a thought tho - have u gauged interest in these? it might be worth investigating before u put a whole load of hours into it. like i say - just a thought.