Thanks for the detailed critique Jazz!

And no, i havn't machined anything in forty odd years and certainly not plastics which weren't around then (that i remeber anyway)

However this presents me a with quandry because we would want our prototype finish has to be very good indeed to impress backers and obtain further funding.

We could change many of the parts to aluminium, but would we achieve a better finish using these machines?

I had a look at a similar machine on www.mydiycnc.com but the owner Stephen hasnt replied to my queries and i cannot access his site this morning to double check parameters. There were options to have the machine fitted with different spindle drives (i think). One i believe was a high speed water cooled unit that should do the trick (perhaps! LOL)

Back to the drawing board!