18 is to be cut thus if only a medially located groove 18 is to be provided as illustrated the grinding wheel 32 is set at the axial midpoint of doffer roll 10 then the installed cam wheel 46 is set at a centerline position with which it should be marked in contact with cam follower roll 44 after which cam wheel 46 is fixed on doffer roll shaft 12 at this setting and biasing tension is restored at spring 48 a check should be made at this stage to be sure that the restored bias of spring 48 has not disturbed the proper location of grinding wheel 32 in relation to doffer roll 10 and an appropriate resetting effected if it has when the foregoing set up has been checked out satisfactorily the doffer roll and grinding unit drive motors 24 and 28 are both started to commence the groove cutting operation for either 27 34 or 12 34 doffer rolls 10 a 6 34 grinding wheel 32 is suitable at a 1 4 34 width a wheel of the 34 saw gumming 34 type provides good groove cutting action although any other reasonably comparable abrasive wheel might be used as well a 1 3 hp 1725 rpm 110 v drive motor 28 is advantageously provided the clothing cover on doffer roll 10 which is normally formed of metallic wire according to current practice is cut to the root of the clothing teeth by feeding the grinding wheel 32 to this depth from handwheel 50 and as the cam wheel and follower system provided will result in reciprocating the.