I’ve also chucked a bushing in the drill press and dressed the end on some sandpaper. Easy to square it up, take off a thousandth or two, etc.
215 RPM, the slowest speed of my drill press.
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I did something similar by spinning the tube in a hand drill and turning on the scotchbrite wheel - probably not quite as square as your idea, but pretty square.
+1, or alternately using a disk sander. Fast and easy way to get them the right length as well.