MIL-DTL-18240 Fastener Element, Self-Locking, Threaded Fastener, 250 Degrees F MaximumThis specification defines the requirements for self-locking elements for use in externally threaded fasteners such as bolts and screws to be used in fasteners with either UNC, UNJC, UNF, UNJF, UNRC or UNRF threads and where the temperatures will not exceed 250 deg. F.

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MIL-DTL-18240F

6.5 Definitions.

6.5.1 Self-locking externally or internally threaded fastener(s). In this specification a

"self-locking externally threaded fastener" refers to bolts, or screws, that incorporate self-locking

elements conforming to this specification.

6.5.2 ON PREVAILING TORQUE. The maximum torque occurring while the fastener is

being installed and prior to development of any axial clamp load.

6.5.3 SEATING TORQUE. The torque required to overcome the self-locking feature and

produce an axial clamp load to the test assembly.

6.5.4 OFF PREVAILING TORQUE. The maximum torque occurring while the fastener is

in motion during the first 360 degrees of rotation in the untighting direction after the test assembly

has been unseated.

6.6 Subject term (keyword) listing.

Plug/Pellet

Strip

Patch

6.7 Changes from previous issue. Marginal notations are not used in this revision to identify

changes with respect to the previous issue due to the extent of the changes.

6.8 Previously manufactured product. Product manufactured prior to the date of this

specification may be used until the supply is exhausted.