Hi John,

sorry for the slow reply; I've been looking at second hand mills online as well as totting up some inital costs. I'm definitely persuaded by your suggestion to start with an existing mill and convert; I hadn't considered that the ballscrews etc in the existing mill could be kept - for some reason i'd imagined replacing them. I think I can probably budget around £2000 for a used mill, which going by ebay looks like it may just be enough for something half decent, though maybe i'll need to splash a little more?

Re. the additional axes on the gantry the existing diy versions i've seen do look pretty complicated.. I think perhaps i'll treat this as a second project, i.e start out with a basic 3 axis and just bear it in mind when i'm doing the z axis that i'll probably want to build onto it at a later date. Manually setting the angle would certainly solve most of my issues for most of the parts I want to produce, so i think this could definitely be an ideal compromise.

Thank you for your guidance on this, it's very much appreciated! I'm working on putting together a proper spec of the components and some cad models, so will definitely be back on here for advice once i've got a more specified design.

Thanks again,

Alex