NADC-75359-30, FINAL REPORT: EFFECTS OF SELF-LOCKING NUTS ON TORQUE-TENSION RELATIONSHIP (29-DEC-1975)

NADC-75359-30, FINAL REPORT: EFFECTS OF SELF-LOCKING NUTS ON TORQUE-TENSION RELATIONSHIP (29-DEC-1975)., esting was conducted to determine torque-tension relationship for self- locking nuts. The test results indicated that torque wit.nch method is not accurate for determining preload when fasteners are preloaded to 75-80 percent of their ultimate tensile strength. The accurdcy of torque wrench method deteriorates even more if fasteners are used for more than one cycle application. There was also significant difference in preload between all metal nuts and ruts with nonmetallic insert. The fastener preload variation decreased with larger fasteners.