Mcmaster carr sells arbors, which are designed to attatch a grinding wheel to a standard motor They have a drilled out "collar" of sorts that slips over the shaft of the motor, and attatches with a set screw. this terminates in a threaded stud with 2 washers and a nut...they work great and are really cheap....I paid $3.50 or so for mine....many sizez to choose from.. Chris