Self-locking Nuts

Self-locking Nuts

Self-locking nuts used in aircrafts meet specifications of strength, corrosion
resistance and heat-resistance. It is advisable to always use a new self-locking nut
each time a component is replaced. Common locations for self-locking nuts are the
engine, fuel control linkages and attachments. There are two types of self-locking
nuts: all-metal nuts and nuts and nuts with non-metallic inserts. Examples of allmetal
nuts are Boots aircraft nut and Flexloc. While, the elastic stop and the nonmetallic
insert lock nut exemplify the non-metallic insert type.

Two primary ways all-metal self-locking nutplates are constructed are either with the
threads in the load-carrying portion of the nut that is out of phase with the threads in
the locking portion. The second construction approach is with a saw-cut top portion
with a pinched-in thread. The locking action of these types depends upon the
resiliency of the metal.

MS21075L3N - MIlitary Fasteners

The elastic stop nut  is constructed with a non-metallic (nylon)
insert, which is designed to lock the nut in place. The insert is unthreaded and has a
smaller diameter than the inside diameter of the nut. Self-locking nuts are generally
suitable for reuse in non-critical applications provided the threads have not been
damaged. If the locking material has not been damaged or permanently distorted, it
can be reused.

Non-self-locking nuts

Castle nut, plain hex nut, wing nut and castellated shear nut are the most common
non-self-locking aircraft nuts. Castle nuts are used with drilled-shank A hex-head bolts, clevis bolts or studs accepting cotter pin or lock wire for safe tying and in
aircraft parts experiencing shearing stresses. Castle nuts are inappropriate in aircraft
parts encountering tension stress. While plain hex nuts suffer a limited uses on
aircraft structure, wing nuts are useful where sufficient tightness is obtainable from
fingers grip, for example in battery connections

Sheet-spring nuts

The sheet-spring nut is made of sheet spring steel and it is cut so that is has two
flaps. The flaps ends are notched to form a hole that is somewhat smaller in
diameter than the screw used. Sheet-spring nuts are typically used when fastening
lightweight components. It other typical applications are for line clamps, electrical
equipment and small access doors. A sheet-spring nut has a definite arch that tends
to flatten out as the screw pulls the flaps in toward the threads. This flattening action
forces the flaps of the nut tightly into the threads of the screw. The springiness of the
sheet-spring nut pushes upward on the screw threads, binding them and locking the
screw in place. With the sheet-spring nut, either a standard or a sheet metal selftapping
screw is used.

Manufactures and Distributors of nuts:

Aerospace Hardware, Inc. –

National Stock – –

What is a Blind Rivet?

What is a Blind Rivet?

The term blind rivet is derived from the word “Blind Job” because it was used when you have only one sided access to a joint. It is made up of two parts, a body and mandrel. The body and mandrel of the rivet are assembled together and are present in different combination of materials according to their usage. Some of the material combination of blind rivet available in the market are:

Aluminum Rivet with Aluminum Mandrel

Aluminum Rivet with Steel Mandrel

Aluminum Rivet with Stainless Steel Mandrel

Steel Rivet with Steel Mandrel

Stainless Steel Rivet with Steel Mandrel

Stainless Steel Rivet with Stainless Steel Mandrel

Plastic Rivet with Plastic Mandrel

This material combination of bind rivet determines their stability as wrong combination can lead to the galvanic corrosion. Blind rivets are available in flat head, countersunk head, and modified flush head.

Blind Rivets

Types of Rivets

What Makes Blind Rivet perfect for Aerospace?

The blind rivets are used for the aerospace applications due to a number of advantages:

They can be used from one side only.

They are very easy to install and don’t need skilled workers.

They are visible through eyes and don’t need expensive apparatus for inspection.

They are reliable because of the unrestricted material and strong connection.

They can be used with two different materials.

Solid Rivets

Aerospace Blind Rivets

What are the Different Types of Blind Rivets?

Blind rivets have many different types, such as: Open End, Close End, Solid Rivets, Semi-Solid Rivets, Multi-Grip Rivets, Peel Rivets, Grooved Rivets, and Hammer Drive Rivets. A complete list of rivets.

Blind Rivets

Aerospace Rivets

What are the Top Brands of Aerospace Blind Rivets?

Alcoa, SPS, and Cherry Aerospace