6.4 Screw jointsGeneralThis section details how to tighten the various types of screw joints on the controller.The instructions and torque values are valid for screw joints comprised of metallicmaterials and do not apply to soft or brittle materials.Tightening torqueBefore tightening any screw, note the following:• Determine whether a standard tightening torque or special torque is to beapplied. The standard torques are specified in the tables below. Any specialtorques are specified in the Repair, Maintenance or Installation proceduredescription. Any special torque specified overrides the standard value.• Use the correct tightening torque for each type of screw joint.• Only use correctly calibrated torque keys.• Always tighten the joint by hand, and never use pneumatical tools.• Use the correct tightening technique, i.e. do not jerk. Tighten the screw in aslow, flowing motion.• Maximum allowed total deviation from the specified value is 10%!The table below specifies the recommended standard tightening torque foroil-lubricated screws with slotted or cross-recess heads.Tightening torque (Nm)Class 4.8, oil-lubricatedDimension0.25M2.50.5M31.2M42.5M55.0M6Product manual - IRC5 3033HAC047136-001 Revision: M© Copyright 2004-2018 ABB. All rights reserved.6 Reference information6.4 Screw joints
