What are Lockbolt Fasteners and How Do They Work?

A Lockbolt fastener is a two-piece fastener consisting of a hardened metal pin and a metal collar that swages into the grooves of the pin to generate a particular, calibrated clamp force to keep components together.

SHEAR STRENGTH

Shear strength is dependent upon the minimum fastener diameter and the material's strength. The shear strength of a fastener may be improved by increasing either its diameter or the quality of the material it is made from.

CLAMP FORCE OR PRELOAD

During the first phases of installation, a tool engages and pulls on the pintail. Before the conical-shaped chamber of the nose assembly is pressed down the collar, the joint is pulled together. This gradually seals it into the grooves of the tougher pin (swages). The combination of the pin and the swaged collar forms the installed fastener. The compression motion decreases the collar's diameter, so expanding its length. In turn, this causes the pin to extend, providing a clamping force across the joint.

TENSILE STRENGTH

Lockbolts' tensile strength relies on the shear resistance of the collar material and the quantity of grooves that it fills.

Avlock International is a leading manufacturer and distributor of specialised fastening systems to both the domestic market and other global destinations. For an obligation-free quote or demonstration, contact Avlock today.