niitti

Niitti, in Finnish, refers to the mechanical fastener known in English as a rivet. A rivet is a short cylindrical shaft with a head on one end. It secures two or more pieces of material by deforming the tail end after insertion, creating a second head and a clamping force that holds the parts together.

Common types of rivets include solid rivets, blind rivets (also called pop rivets), tubular rivets, semi-tubular rivets, and split rivets. Solid rivets require access to both sides of the joint for installation, typically using a hammer and a bucking bar or a pneumatic rivet tool. Blind rivets can be installed from one side with a tool that pulls the mandrel to form the second head. Tubular and semi-tubular rivets are variations designed for specific strength and installation characteristics.

Rivets are made from a variety of materials, including aluminum, steel, stainless steel, copper, and titanium, chosen for factors such as strength, weight, and corrosion resistance. They are used in many industries, including construction, aerospace, automotive, shipbuilding, and electronics enclosures. The choice of rivet size, material, and hole diameter affects the joint’s shear and tensile strength.

Installation involves drilling a properly sized hole, inserting the rivet, and deforming the tail to form the second head. Solid rivets require access to both sides of the assembly, while blind rivets are designed for one-sided access. Riveting is valued for creating permanent, vibration-resistant joints and for its simplicity and reliability, though it is typically less removable and adjustable than threaded fasteners. Riveting has ancient origins and became widespread with modern fabrication techniques and aerospace applications.