I want to drill a hole in plywood to pass a flex through. The flex will be moved through the hole from time to time so to protect it I want it to pass through a bit of brass tube ( about 10mm id) with a sort of collar or shoulder which will also make the hole look tidier. I have searched for "collared brass tube", " brass bushing", " brass grommet", etc. But can't seem to find what I want. Any ideas would be very welcome!