A good local hardware store should have Teflon (or equivalent) bushings. then just fine the closest correct out side diameter. If the inside diameter is to large another bushing can be used inside the first. Preferably the hole will be too small and then you just need to enlarge the hole. The best and only truly correct way would be to buy the exact right size from online or take some Teflon round stock and machine it to the correct dimensions.