Ferrule

A ferrule is a metal ring, band, or sleeve used to join, reinforce, or seal the end of a tube, pipe, or handle. The term covers a surprisingly wide range of objects — from the tiny aluminium band that holds an eraser on a pencil to the heavy steel collars on hydraulic hoses.

Common examples

• Pencil ferrule: The crimped aluminium band that holds the rubber eraser to the end of a wooden pencil. Two sets of crimps grip the wood and the rubber respectively.
• Brush ferrule: The metal band that binds the bristles of a paintbrush to the handle. Tin or brass, crimped or soldered.
• Tool handle ferrule: The metal ring at the end of a chisel, file, or screwdriver handle that prevents the wood from splitting when the tang is driven in.
• Shoelace aglet: The plastic or metal sleeve at the end of a shoelace — technically a ferrule that prevents the lace from unravelling.
• Pipe ferrule (olive): The soft metal ring in a compression fitting that deforms to create a seal between the tube and the fitting body.
• Wire rope ferrule: A metal sleeve swaged onto the end of a wire rope to form a loop or prevent fraying.

Materials

Ferrules are made from aluminium, brass, copper, steel, or plastic depending on the application. The material must be soft enough to deform under crimping or swaging but strong enough to hold under load.