That mirror-bright finish you see inside and out on small metal parts designed to fit together with precision usually is done on a lathe with a toolpost grinder.
In a toolpost-grinder setup, both the wheel and the work are rotated simultaneously in opposite directions, a procedure that produces a finish on metals that just can't be equaled by any other finishing process.
The frame of this toolpost grinder is made from ordinary steel pipe fittings. If care is used in selecting, machining and assembling the parts, it will do very accurate work which is acceptable for all practical purposes.
Four pages ( 3 sheets - front on first and third sheet, front and back on second sheet )
B & W photos, illustrations, expanded views, and instructional narrative.
My plans are from original source materials such as books, magazines and other publications and the pages are carefully removed.