Bolts and Set Screws – Are they interchangeable?

Prof. Saman Fernando – Centre for Sustainable Infrastructure SUT

Full PFD here

Introduction:

This technical note discusses the definitions, standards and variations pertaining to bolts and screws. Also this highlights the applications where bolts and screws could be used after due consideration given on their suitability with respect to each application. At conclusion, this technical note provides the key criteria for determining the suitability of product based on the application in tabulated form.

Definition of Bolt and Screw (+ Stud): The words Bolt, Screw and Stud are used commonly in bolting technology. Therefore it is necessary to have a clear understanding of the differences in geometries of these three components.

Bolt: Has a Head, longer unthreaded Shank Portion, Thread and a Drive Feature. Bolt is generally tightened with a nut or a threaded- through hole or a blind hole.

Screw: Similar to a bolt but has a much longer thread almost to the head. It can be tightened with a nut or a threaded-through hole or a blind hole. In some instances, a screw could cut or form its own thread (eg. timber screws, thread forming screws). Stud: A stud does not have a Head. It may have a drive feature. It could be threaded at one end, at either end or all the way. It can be used with one or two nuts, as a Screw or as a Bolt.

Stud: A stud does not have a Head. It may have a drive feature. It could be threaded at one end, at either end or all the way. It can be used with one or two nuts, as a Screw or as a Bolt.