A look at locking and breakaway torque performance of our locking inserts
Locking torque and breakaway torque are critical measurements for fasteners in aerospace applications. Measuring locking torque and breakaway torque throughout 50 cycles gives users a clear indication of how a self-locking fastener will behave throughout its life cycle.
NASM25027 requires that manufacturing lot of locknuts be tested in 15-cycle torque tests with 100% of the sample set passing. If the nut being tested requires crimping and the entire sample lot doesn’t pass the torque tests, the whole manufacturing lot must be scrapped as crimped nuts cannot be reworked.
Manufacturers have developed tricks to help pass the tests, including changing the bolts, cleaning the bolts between cycles, and allowing cooldown periods.
In our tests, Sky Climber Fasteners used 50 cycles instead of 15 and did not change bolts nor cleaned or cooled materials between cycles. We believe this more closely mimics real-world use scenarios. Our ability to certify to 50 cycles in the NASM25027 torque test gives our customers confidence that our nuts can be reinstalled without loosening during service.
When combined with our Rhino locknuts, Titan Barrel nuts, or other fastener designs, our threaded locking inserts perform consistently through 50 cycles with no significant loss in torque. For example, test results for our ½-inch -20 nuts show locking torque results averaged close to 30 in-lbs with little deviation in performance — well below the 150 in-lb maximum requirements set by MS25027. Breakaway torque measurements averaged 30 in-lbs with deviation throughout a 50-cycle test. This is consistently greater than the 18 in-lb minimum set by MS25027.
Visit any of our product pages to learn more about how our locking insert technology makes our fasteners the lightest, strongest, and best performing fasteners available in the market today.