The ones I should have received should have been 3/4. .750ND x 5/8. .625 ID but what I got was .740 OD x .610 ID so that was too loose and ID too tight. I had to return them and find more accurate ones.
To install cotton or fiber buffs that spin accurately, you need correctly sized steel bushings like these and large washers to allow the wheels to hold their shape and stay tight to the shaft you are using . Use for work.
I went to every hardware store in Phoenix even the specialty stores and all the adapters from 3/4 to 5/8 were actually there was the wrong size. I took a chance with them and they are perfect! Imagine someone making a piece of metal and knowing the real ID and Od! Thanks very much!