TR TR U US S TED T . ED Williams Torque Wrenches provide high torque accuracy and repeatability. WHY PROPER TORQUE IS SO IMPORTANT! It’s about safety, reliability, and performance. EVERY manufacturer, whether it’s in aerospace, motor vehicles, precision equipment, power generation, etc., specifies critical fastener torque for important reasons; under or over tightening critical fasteners can lead to product failure. And product failure means downtime, higher costs, potential injury, and more. 290 300 310 330 340 350 320 0 10 20 30 40 50 60 70 280 80 270 90 260 100 110 120 130 WHAT IS TORQUE? Torque is rotational or turning force. Torque is measured in length and force: Length means dis- tance from “center of drive” to “center of handle". Force means “pounds”, “Newtons” etc. HEAD FRICTION 45% of Applied Torque BOLT STRETCH 10% of Applied Torque 290 250 240 230 TORQUE (Turning Force) FORCE (Pressure Applied) 140 150 210 220 160 170 180 190 200 LENGTH (Distance from pivot point to force) EXAMPLE: Apply 80 ft. lbs. of torque, then apply 90 degrees of rotation HOW DO YOU CALCULATE TORQUE? Torque = Length × Force WHAT IS TORQUE PLUS ANGLE? The standard torque formula used to calculate torque is: “L x F = T" Torque Plus Angle creates a EXAMPLE: 2 ft. (length) x 30 lbs. (amount of force at center of handle) equals 60 ft. lbs. of torque (60 Ft. Lbs.) more exact clamp load for torque-sensitive equipment. 330 340 350 320 0 10 20 30 40 230 240 250 260 270 280 290 300 310 50 THREAD FRICTION Up to 45% of Applied Torque 60 70 330 340 350 320 0 10 20 30 40 310 50 WHAT DOES TORQUE DO? 80 300 60 90 Torque creates a "Clamp Load" to join two pieces of material. 290 100 70 • Bolts (or threaded fasteners), are designed to create clamping force, also called “clamp load”. 280 80 • When torque is applied to a threaded fastener, it draws together the joint, (two pieces of material). 270 • As additional torque is applied to the fastener, the joint is pulled together creating a clamp load 110 120 130 260 250 140 150 160 170 180 190 200 210 220 90 100 110 120 130 as the fastener begins the stretching process. It’s this fastener stretch that creates and maintains clamping force, like a stretched bungee cord maintaining tension. LOAD 240 230 •––ThTTehheeacamtmuaaotel 3 u 2 ra 0 niamt 3 l 3 oo 0 afun 3 t 4 ndo 0 trgq 3 o 5 ruf 0 acedlaae 0 mpopfp 1 l 0 tilheoed 2 a 0 dftaoi 3 ss 0 tthede 4 ne 0 eftaer.srmteinneerd. by several factors: 300 310 140 150 160 170 180 190 200 210 220 60 50 Distributed over – The external friction on the joint – friction under the fastener head, and friction between the all threads threads of the fastener and material it’s connected to. 70 280 80 270 90 260 100 250 240 230 110 120 130 150 140 220 210 160 170 180 190 200 WHY IS APPLYING PROPER TORQUE IMPORTANT? Creating proper Clamp Load prevents damage and equipment failures. • Safety & Performance: Applying accurate torque is critical to assembly applications, engines and precision equipment. • Creating a proper clamp load is the main objective when applying torque to a fastener. Engine cylinder heads, pipe coupling, wheels, all need to be “clamped” uniformly to specific torque values. • There are three main factors that affect the correct application of torque: (1) Condition of components, (2) Accuracy of torque instrument, (3) Properly applied torque values. • Applying torque incorrectly can lead to stripped threads, premature loosening or broken fasteners that can cause catastrophic failure. Leaking joints may cause engine or equipment failures. 2
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