I get the bronze bushings at my local Tru Value hardware store. If they are out of them, the local Ace hardware store usually has them. I don't recall what the exact diameter is, but I use a 5/8 inch drill bit on the wheel and the bushings that I buy will slide right in. Sometimes I have to use a soft hammer and a correct size socket to tap them in. Combine all of this with new axle bolts, and you will have wheels that will turn smoothly without excess wobble.