Torque Tables And Conversion Charts - Section 12 02/11 OM1200 Page 12-2 EFFECT OF SPECIAL LUBRICANTS On Fasteners and Standard Torque Values STANDARD TIGHTENING TORQUES For Class 10.9 Cap screws & Class 10 Nuts The Komatsu engineering department does not recommend the use of special friction-reducing lubricants, such as Copper Coat, Never-Seez®, and other similar products, on the threads of standard fasteners where standard torque values are applied. The use of special friction-reducing lubricants will significantly alter the clamping force being applied to fasteners during the tightening process.
The following specifications apply to required assembly torques for all metric class 10.9 finished hexagon head cap screws and class 10 nuts. Cap screw threads and seats shall not be lubricated when assembled. These specifications are based on all cap screws, nuts, and hardened washers being phosphate and oil coated. If special friction-reducing lubricants are used with the standard torque values listed in this chapter, excessive stress and possible breakage of the fasteners may result.
If zinc-plated hardware is used, each piece must be lubricated with simple lithium base chassis grease (multi-purpose EP NLGI) or a rust preventive grease (see list, this page) to achieve the same clamping forces provided below. Where the torque tables specify “Lubricated Threads” for the standard torque values listed, these standard torque values are to be used with simple lithium base chassis grease (multi-purpose EP NLGI) or a rust-preventive grease (see below) on the threads and seats unless specified otherwise. Torques are calculated to give a clamping force of approximately 75% of proof load. The maximum torque tolerance shall be within ±10% of the torque value shown.
In the following table under “Cap Screw Size”, the first number represents the shank diameter (mm). The second number represents threads per millimeter. NOTE: Ensure the threads of fasteners and tapped holes are free of burrs and other imperfections before assembling. Example: M20 x 2.25 Suggested* Sources for Rust Preventive Grease: M20 = shank diameter (20 mm) American Anti-Rust Grease #3-X from Standard Oil Company (also American Oil Co.) 2.25 = thread pitch in millimeters Gulf NoRust #3 from Gulf Oil Company. Mobilarma 355, Product No. 66705 from Mobil Oil Corporation. Rust Ban 326 from Humble Oil Company. Rustolene B Grease from Sinclair Oil Co.
Rust Preventive Grease - Code 312 from the Southwest Grease and Oil Company. NOTE: This list represents the current engineering approved sources for use in Komatsu manufacture. It is not exclusive. Other products may meet the same specifications of this list. TABLE 1. Standard Tightening Torque for Metric Class 10.9 Cap screws & Class 10 Nuts Cap Screw Size Torque N•m Torque ft lb Torque kg•m M6 x1 12 9 1.22 M8 x 1.25 30 22 3.06 M10 x 1.5 55 40 5.61 M12 x 1.75 95 70 9.69 M14 x 2 155 114 15.81 M16 x 2 240 177 24.48 M20 x 2.25 465 343 47.43 M24 x 3 800 590 81.6 M30 x 3.5 1600 1180 163.2 M36 x 4 2750 2028 280.5