Fastener SAFETY Seminar F A S T E N E R Fastener Facts S A F E T - PowerPoint PPT Presentation

Fastener SAFETY Seminar

F A S T E N E R Fastener Facts S A F E T Y S E M I N A R OF ALL CONNECTIONS OR 70% JOINTS ARE HELD TOGETHER WITH FASTENERS OF PRODUCTION TIME IS 80% SPENT ON ASSEMBLY OF FASTENERS REPRESENTS IN PLACE 50% FASTENER ASSEMBLED COSTS

F A S T E N E R Common Fastener Failures S A F E T Y S E M I N A R Stripped Threads Permanently Cracked, Bent, Broken Stretched Mushrooming of Dishing of Washer Nut Page 2

F A S T E N E R NASA Study of Fastener Failures S A F E T Y S E M I N A R Percent of Failure Assembly 24% Damaged 23% 29% Design Parts 14% 10% Pre-load Defects

F A S T E N E R Fasteners In The News S A F E T Y S E M I N A R Reprinted from AUTOMOTIVE NEWS COMPUTERIZED TESTING SOLVES GM’S V-6 PROBLEM Dale Jewett Engineering Editor Ann Arbor, Mich.—General The automaker sent the engine and its prevented them from working loose and fixed the problem. Motors had a problem with a V-6 computerized design information to an engine. Many times the engine was Ann Arbor firm to see if it could help. The testing firm’s main tool is finite element analysis: being wrecked because a connecting In three weeks the problem was rod cap would break off and be found: Bolts holding the cap on the computerized, testing thrown around the crankcase. connecting rod were not being of parts and systems to simulate s tress and temperature loads. Beefing up the cap and the mating tightened enough. area on the connecting rod didn’t help, GM’s machines were set to measure Automakers are now adding such computerized testing capabilities. and more times than not, throwing the bolt torque, but not the torque angle. more metal and money at the problem Additional tightening of the bolts is the wrong answer.

F A S T E N E R S A F E T Y S E M I N A R

F A S T E N E R Commercial Grade Capscrews S A F E T Y S E M I N A R Page 4 & 5

F A S T E N E R Maintenance Engineered Capscrews S A F E T Y S E M I N A R Page 4 & 5

F A S T E N E R Hex Nut Grade Markings S A F E T Y S E M I N A R 60° Page 6 & 7

F A S T E N E R Common Washer Markings S A F E T Y S E M I N A R Page 8 & 9

F A S T E N E R Stress - Strain Diagram S A F E T Y S E M I N A R Elastic Plastic Ultimate Tensile Strength Range Range AXIAL TENSILE LOAD, lbs. Proof Load Yield Point Clamp Load Failure (Tensile Break) 0 AXIAL ELONGATION Page 10

Fatigue Failure in Common Bolted F A S T E N E R S A F E T Y Joints S E M I N A R 15% 65% 20% 2 Key Reasons: 1. Insufficient torque at installation 2. Loss of Clamp Load in service

Fatigue Failure in Common Bolted F A S T E N E R S A F E T Y Joints S E M I N A R UNJ UNR UN

F A S T E N E R Common Fastener Failures S A F E T Y S E M I N A R Burnishing No Stretch Straight Break Flattened/ Worn Threads Page 20

F A S T E N E R Lockwashers S A F E T Y S E M I N A R

F A S T E N E R Locknuts S A F E T Y S E M I N A R Grade of Nut Tensile Strength of ….. Bolt (ksi) Grade A Not greater than 90 Grade B and F Not greater than 120 Grade C Not less than 105, …………. nor greater than 150 Grade G Not less than 120, nor greater than 150

Wedge-locking action uses tension F A S T E N E R S A F E T Y instead of friction (Shur-Loc) S E M I N A R The teeth seat into the mating surfaces allowing movement only across the face of the cams. When a bolt attempts to loosen. the pair of washers expand more than the corresponding pitch of the thread. The tension created helps to positively lock the fastener in a joint which is subjected to any kind of vibration or dynamic loads

F A S T E N E R Where are Shur-Loc Washers Used? S A F E T Y S E M I N A R On the connection between the Rammer – rock hammer adapter plate and the machine body

F A S T E N E R Where are Shur-Loc Washers Used? S A F E T Y S E M I N A R The Screen Machine – topsoil shredder

F A S T E N E R Where are Shur-Loc Washers Used? S A F E T Y S E M I N A R Tidaplast AB – fastener for flag staff

Fastener SAFETY Seminar

F A S T E N E R Coarse Threads vs. Fine Threads S A F E T Y S E M I N A R

F A S T E N E R Metric Mechanical Properties S A F E T Y S E M I N A R MPa: Megapascal (1 MPa = 145 psi) Page 16 & 17

F A S T E N E R Metric Head Markings S A F E T Y S E M I N A R Page 16 & 17

F A S T E N E R Thread Identification S A F E T Y S E M I N A R Fractional Measured in number of threads per inch Thread Pitch Metric Measured in distance between peaks of thread Page 13