3mtr CNC pipe profiling machine.

[D-man]

ok this ill give you an idea what im trying to achieve

[irving2008]

are you planning to mill the holes or use a hole saw? the latter could simplify things and reduce the need for high rigidity at the expense of potentially needing tool changes if there are variable hole sizes. obviously you couldnt do rectangular cutouts.

Also I'd consider mounting the spindle horizontally on a sliding carrier rather than a gantry (think lathe toolholder) so it drills in from the side. easier to make it rigid for large diameter workpieces.

Do you need a chuck? one with internal jaws that expands to 220mm is going to be heavy and expensive, although i realise you wont be spinning it at any speed. Why not use a stepped cone each end with a screw-down clamp (big jubilee clip maybe?)

The back of the cone could have index holes to manually lock it against a static support at 60 & 90 degree steps. you could add stepper later if you wanted.