GENERAL BOLTING TORQUE SPECIFICATION

 

Grade Tensile.Min. Hardness Bolt Dia. Torque  
SAE 8 150,000 Psi. HRC33-39 3/8" 50 ft-lbs  
      7/16" 80 ft-lbs  
      1/2" 120 ft-lbs  
      3/4" 400 ft-lbs  
      7/8" 700 ft-lbs  
SAE 9 180,000 Psi. HRC38-42 3/8" 60 ft-lbs Bownalloy
      7/16" 100 ft-lbs  
      1/2" 150 ft-lbs  
      3/4" 500 ft-lbs  
      7/8" 800 ft-lbs  
Class 10.9 1040 Mpa. HRC33-39 10mm 8.2 kg-m  
      14mm 23 kg-m  
      16mm 36 kg-m  
      18mm 49 kg-m  
      22mm 95 kg-m  
Class 12.9 1220 Mpa. HRC38-42 10mm 10 kg-m  
      14mm 27 kg-m  
      16mm 45 kg-m  
      18mm 59 kg-m  
      22mm 114 kg-m  

The above bolts are common use on main, head, and other application except connect rod. Material for these bolts are medium carbon alloy steel with quench & temper process.