Aircraft Fasteners

The word FASTENER is used to describe all of the various types of fastening device used in the construction of an aeroplane. This is because the meanings of the words BOLT and SCREW for example, may be interpreted differently by separate organisations.

A bolt is an externally threaded fastener designed for insertion through holes in the assembled parts. Bolts usually have a plain (unthreaded) portion on the shank. A bolt is normally intended to be tightened or released by turning or torquing the nut.

 A screw is an externally threaded fastener capable of being screwed into preformed threads in the assembled parts. It is normally intended to be tightened or released by turning or torquing the head. A screw has a fully threaded shank. Certain types of screw such as self tapping screws and woodscrews form a thread when they are screwed into place.

A standard fastener comprises of a threaded portion, a head and sometimes a plain shank or grip.  Between the shank and the thread is a small tapered transition zone.  Between the shank and the head is stress relieving fillet radius.

A fastener will be defined by a number of features which are given in detail in it’s specification.  These include it’s Thread Form, Shank Diameter, Head Style, Grip Length, Material, Surface Finish and Locking Facilities.