FALL 2024

154 THE DISTRIBUTOR’S

154 THE DISTRIBUTOR’S LINK GUY AVELLON WHAT FASTENER DISTRIBUTORS NEED TO KNOW ABOUT HOW TO INVESTIGATE FASTENER FAILURES from page 134 fatigue because a high compression rate is created as the nut slams into the joint surface. This compressive force has an equal and opposite reaction or recoil which will leave the joint not as tight as expected. Too much impacting with an air tool can also crack the adjacent area around the nut. FAILED STAINLESS STEEL How Was The Fastener Installed? This makes a huge difference because a fastener can never be evenly tightened by hand with a hand wrench. Thread frictions vary and so does the installer’s ‘feel’. Sometimes the handle length of standard wrenches does not provide the proper leverage for higher grades of fasteners. Torque wrenches are fine but not always accurate due to a multitude of variables, most include friction. Pneumatic wrenches are mostly unregulated to output torque. They try to seek a stall point from thread friction. If the threads were lubricated, they would have either stripped the nut threads or stretched the fastener into yield. Air wrenches are quick. They can cause galling and thread locking of stainless steel fasteners, even if they are of different types of stainless: it is the speed that destroys the fastener. The speed of assembly can also cause an underloaded joint and subsequent metal The impact wrench will always leave tell-tale signs of abuse. In the photograph above, the hex corners of the nut clearly displays markings from the socket on the installation side (right) of the hex corners. There are also markings on the off side (left) which appear not only from removal but from the recoil of the socket as the impact goes forward and instantly recoils back. With proper investigative techniques, the causeeffect of failures can be determined so that preventive measures can be employed. GUY AVELLON

MWFA FSTNR WEEK ’24 TABLE TOP SHOW AND FASTENER BASH - AUGUST 20, 2024