I need to make a single piece (therefore automation not necessary). The PVC pipe in question is approximately 490mm long and has a 20mm diameter. I would like to cut four 60° arcs, the location of the cuts along the circumference of the cross section must be within a ±20° tolerance and the cuts must be within a 70° ± 10° tolerance. Cuts cannot extend beyond the corners, if the cut goes to far then the entire hole must become larger too. The width of the cuts (measurement on the long axis of the pipe) can be of any length longer than 3mm. How would I cut out the arcs and what tools would I need? I have provided diagrams below. Thanks in advance.
(I stretched the diameter of the pipe in the diagrams 10x both to make them easier on the eyes and to provide space for annotating)
Note: I am unexperienced in this sort of thing but I am sure that there is a better solution than using a handheld grinder and hoping for the best so I am asking.