By checking the torque after assembly, you not only verify adequate torque was delivered to the fastener, but may also detect missed or loose fasteners, or joint relaxation. Many users may want to verify residual torque. What is Residual Torque? It is the amount of tension that remains in a joint after fastening a threaded fastener. The torque required to return the fastener to its original location is the reference to the original torque applied to the fastener. This time loosen the fastener and retighten until the marks on both application and fastener are aligned. The torque value to loosen the fastener is the approximate torque that was applied to the joint.ģ) Marking Test - Once the fastener tightened, mark clearly the surface of the fastener, nut or bolt and continuing the mark onto the surface being clamped for reference. At the point the fastener breaks loose, the torque reading is recorded. This is the best way to determine residual torque.Ģ) Loosening Test - This is a similar process to the first movement test described above, except instead of the tightening the fastener, the torque is applied in the direction that loosens the fastener. The reading recorded is a good indication of the original torque applied to the joint. In the tightening direction, begin to slowly apply force to the tool until the first movement in the fastener is noted.
Mark the tightened fastener and surrounding application.
To perform this test, there are three common methods that have been established to provide an accurate reference to the applied torque.ġ) First Movement Test - Once the fastener has been tightened, employ the use of torque measuring tool.
HOW TO FIND TORQUE SPECS IN CAT SIS ISO
It is important for many companies to ensure that proper torque is being applied and maintains gauge requirements associated with the ISO 9001 Quality Standard. Fasteners that are insufficiently torqued can vibrate loose and excessive torque can strip threaded fasteners. The failure of a three-cent fastener that isn't properly tightened can lead to catastrophic or latent failures. It is important to audit the joint for accuracy and to ensure your product's quality, safety and reliability isn't compromised. Once a torque specification is determined, the joint should be audited to verify the product has been fastened to the specified torque.