This is what 4 hours in CAD gets me, a 3D Printable rotary tool (Dremel) adjustable Delta arm cutting jig for 6mm Carbon Fibre OD tube. My rotary tool (cheap one) has a flexible extension so it clamps that in place on a hinge, The long rods are 8mm threaded bar which screws into the cutting side held in place by nut traps and the endstop is held in place by nuts and washers once set to the correct size.
