This design standard provides information on the use of self-locking shank nuts, thread sizes .1640-36 thru .3750-24, together with details of flange hole and abutment shoulder for their installation.

Purpose

To standardize on the dimensional particulars of the attachment flange hole, abutment shoulder, and length of shank on the nut.

Application

Primarily for aerospace propulsion system blind bolted applications where high temperature self- locking double hexagon nuts cannot be used.

Description

A self-locking shank nut is held captive by flaring the shank into a countersink in the flanged component. The nut is prevented from turning during the assembly and removal of the bolt by means of a flat on the nut that abuts a machined shoulder on the flanged component part (see Figure 1).