Round Head Bolt

A round head bolt has a domed head and is used for general fastening where a rounded head is acceptable. It often has a square or hex neck under the head.

A round head 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 used in general engineering and in outdoor work where the finish suits the site.

Hot dip galvanising gives a thick zinc coating for outdoor and corrosive use. Plain finish has no coating and suits dry indoor use. PTFE coating gives low friction and some chemical resistance.

This kind of bolt is often made in stainless steel 304, stainless steel 316, high tensile steel, mild steel or brass. Stainless steel 316 gives better corrosion resistance than 304. Brass is used for electrical and decorative work.

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

Ask for a certificate of conformance and check the head marking, thread and finish on receipt. A mill test certificate can be requested for the material.