"ALUMINUM ALLOY QQ-A-601 ALLOY 356-T6 COMP 3,ANODIZED BPS FW4001,SHAPE CIRCULAR,DIM.,3.500 IN. NOM OD,0.300 IN. NOM HT,2.800 IN. NOM ID BY 0.180 IN. DEEP,ONE GROOVE ON LEFT ID SIDE 2.950 IN. DIA BY 0.157 IN. W BY 0.175 IN. DEEP,ONE CENTER HOLE IN COVER 0.253 IN. DIA,ONE BOSS PER AND10050-6 ON VERTICAL CENTERLINE 1.075 IN. FROM CENTER W/0.562-18 UNF CLASS 3B THREADS,ITEM USED ON MAIN ROTOR GRIP"