A sample grinder includes a base having a bowl and a rotatable drive plate to operably support a grinding wheel. A head is configured to support a specimen holder and has a first drive for rotational drive of the specimen holder and a second drive for moving the head and specimen holder toward and away from the drive plate. The head has a sleeve that is larger than the specimen holder. A cover is disposed over the bowl and has an opening larger than the sleeve so that the sleeve fits through the opening when the specimen holder is moved toward the rotatable drive plate. The grinding wheel is mountable to the plate in a single radial orientation only. A dressing system is operably connected to a controller to monitor the current of the drive plate motor and/or the head first drive actuates the dressing system based upon the current drawn by the drive plate motor and/or the head first drive motor falling below a predetermined value.