For these razors I used a 6 inch diameter wheel. I have the Ameribrade Fastback machine with variable speed and reverse, it's a great machine with a lot of power. I have the following contact wheels: 10",6",4",3",2",1" (small wheel). I used one of the blanks to replicate the Korn Patent Hollow Grind using a combination of the smaller wheels, came out very nice but I dropped the razor accidentally and it cracked a third of the way in from the toe :(