THIS MIL-MASTER OR MIL-RITE BLACK" course Thread"ADJUSTMENT KNOB COMES WITH THREE WASHERS. THIS KNOB IS FOR BOTH THE MIL-RITE AND THE MIL-MASTER MILLS FOR ADJUSTING THE FLOUR TEXTURE SETTING ON THE GRINDERS. PLEASE BEFORE ORDERING CHECK THREADS ON KNOB. THERE ARE TWO SIZES OF THREADS ON OUR MILLS, EITHER THE FINE THREAD (24 THREADS PER INCH) OR THE COARSE THREAD (18 INCHES PER THREAD). THE BEST WAY TO FIND OUT THE SIZE YOU NEED IS TO LOCATE A KNOWN BOLT THAT WILL SCREW INTO YOUR SHAFT AND THEN ORDER IT FROM US. YOU MAY ALSO E-MAIL US FOR TECHNICAL HELP IF THAT IS EASIER FOR YOU.