the dob rim's wont grind to well with the every day normal grinding disc........how ever ive had a talk with my pops about them....he is a smart arse and knows shed loads lol. when he was working with verry fine metals....he used a verry thin and flexable grinding disc .its almost like cardboard with a high grade sand paper affect... he is 100% shure that this will give you a nice deep sharp grind ....with out taking as much material off the rim if u were to use a cutting/grinding disc. had a old rim bashing around so i ground one side of the rim using a cutting/grinding disc....thought yeah good grind... then on the other side i used this flext sand paper disc thing......now no word of a lie...the more you flext this disc in to the rim the deeper and sharper the grind comes out..after brushing all the shards of the rim.....i felt the grind and it actually cut my finger open so try and get your self one of thees disc max and try that and let me know how it goes just thought id share my info with you all who may want to run thees dob rims dave x