Relevant British Standards
BS 4439:1969..Specification for screwed studs for general purposes. Metric series

A stud (stud-bolt) is a round metal bar screwed at both ends or fully screwed.    Engineered studbolts can also have flanges at a set distance from one screwed end which provides a positive collar against which the stud is tightened.

An important application form this type of fastening is for internal combustion engine cylinder blocks.  The cylinder head is normally fastened to the cylinder block using stud bolts. The studs are fitted onto engineered tapped holes in the block.   The projecting studs are convenient guides for locating the associated holes in the cylinder head . The head is fastened down using nuts on the studbolts.   This type of assembly is also used for special flanges, tank lids, pressure vessel inspection covers, and car wheels.  With stud fastening the nut has the ability to "float" and adjust on the nut end threads, which is not possible on a bolt...when fastening into deep tapped hole, this feature becomes even more important.

Studs are used with anchor fixings in civil and architectural engineering and when fastening machinery to concrete flooring.

There are also engineering applications when studbolts ( with two nuts ) are used in place of bolts.   These are generally highly loaded , large dia, long bolted items for which the material control and heat treatment is more economically completed on a stud as opposed to a bolt.  For high load-high duty applications, high strength stud-bolts can provide significant advantages if properly engineered.   The use of special nuts with close tolerances and specially contoured internal threads can allow distribution of the stress.   Studbolts are widely used in the petrochemical and nuclear industry .


The advantages and disadvantaages of studbolts joints over conventional bolted joints are listed below:

Relevant British Standards
BS 7670-2:1997..Steel nuts and bolts for resistance projection welding. Specification for welding of weld nuts and weld bolts



For low duty applications for thin plate and sheet steel assemblies the weld stud provides a convenient reliable method of fastening flanged joints and removable covers.   The stud welding procedure simply involves positioning a special stud against the flange face using a special welding gun. The gun is operated and the stud is automatically welded to the face..

The advantages and disadvantages of the welding stud joint are listed below..

The two main stud welding processes are Capacitor Discharge method (CD) and the Arc Stud Weld Process

Capacitor Discharge (CD) stud welding is generally used to weld smaller diameter fasteners to thin base metals.  Because the weld cycle is completed in milliseconds, welds can be made without distortion or , burn-through .   As long as one end of the fastener is designed for CD welding, CD studs can be manufactured in various shapes.

Arc stud welding is generally used to weld large diameter fasteners to rougher and thicker base metals.   Arc studs may be almost any shape and there are literally hundreds, however, they must have one end of the fastener designed for Arc welding.   Mild steel, stainless steel, and aluminum are applicable materials for Arc stud welding.