I'm slotting, and then enlarging the ID of a 1/2 x 1" x 1/8 wall alum rect tube with a 1/4" T-slot cutter (about .235 x .563). The nominal ID of this tube is .25 x .75, and I am enlarging it to about .320 x .760. Any given roughing or finish "cycle" will require 4 passes -- which add up on 80" tubing. This is being done on a gantry mill, flood coolant pressure is limited, so chip removal is a bit of an issue.
Would it be prohibitive to have a .320 x .760 custom cutter made? 1/4 T-slot cutters are anywhere from $30 to $100, in HSS or cobalt, staggered tooth. Haven't seen carbide. Will a custom cutter cut as well as a stock cutter? Will limited chip clearance nix this strategy from the gitgo? Any sources for getting one made?
I won't be doing this forever. When I work out the bugs of the basic design, I will bite the bullet and have this form extruded from a mill. But I will proly be doing this for a while, so if it's at all practical and can make my life less effingly miserable in the meantime, I'd go for it.