Bolt

A bolt is a threaded fastener that passes through holes in parts and tightens with a nut. It holds assemblies together and can be taken apart again.

A bolt clamps two or more parts through a drilled hole. It takes a nut and often a washer of the same thread and class. It can be matched with a spanner or socket of the correct size.

Hot dip galvanising gives a thick zinc coating for outdoor and corrosive use. PTFE coating lowers friction and helps with repeated tightening. Zinc flake coating gives corrosion protection without hydrogen embrittlement risk.

This kind of bolt is often made in steel, alloy steel, stainless steel, brass, bronze, copper, nickel, plastic or high nickel alloys. Stainless steel 316 resists corrosion in wet and chemical conditions. Alloy steel gives high strength for heavy duty joints.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a mill test certificate or certificate of conformance for the heat and grade. On receipt, check the head marking, thread form and coating thickness. Confirm the dimensions match the drawing before use.