Questions on using a moving gantry style mini-mill...

[JAZZCNC]

What sort (if any) lube/coolant do you use on aluminium? I have enough parts in now to build a pressurised fog-less system but just wondering what people put in them :)

I use WD40 type lube but oil/parafin mix will work.

Back to the CAM, shapes like the odd shaped internal part on my drawing, I have roughed out the bulk with a 5mm tool, that leaves of course 2.5mm rads in all the corners, are you saying to finish cut that with the 2mm tool in one pass?

Yes will be ok in this case because your now side cutting and the tiny amount left won't hurt anything. However it's not recommended to use same size tool as the radius. ie: 2mm Rad use use 1.9mm or smaller Dia tool. This means the tool won't be cutting on two sides in the corner so won't chatter or snag and break the tool. Which can happen on really small tools. Larger tools just usually leave mark in corners and make horrible noise.

Do lead-ins and outs feature or forget them for the minute?

Well they are all part the process really so should happen anyway. For instance you'll ramp into pockets for roughing to safe tool wear but radius arc into the Finish pass if enough room for better finish. If cam program allows I always let the lead out go slightly past the lean In point as well to remove cross over point.