Double and Single End Studs

Double End Studs are threaded fasteners that have a thread on both ends with an unthreaded portion in between the two threaded ends. Double End Studs or Double end Stud Bolts are threaded rods with thread at both ends and a plain shank equal to that of the nominal diameter; and are designed to be used where one of the threaded ends is installed in a tapped hole and a hex nut used on the other end to clamp a fixture onto the surface that the stud has been threaded into.
Another name that is also sometimes used for Double End Studs is Tap End Stud or “fitted stud”. A Tap End Stud will have different thread lengths on both ends. It has one short thread intended to be used in a tapped hole and often will have Class 5 fit threads to ensure full engagement.
Note that for Metric Double Ends Studs the short thread is not included in the nominal length of the stud. Double-end studs are used for flange bolting or other applications where torching from both ends is necessary or desirable.
Since a double end stud bolt has threads on both sides, it can more easily be used to fasten two components, usually with hex nuts (sometimes locknuts). During the tightening process of a double ended studs, washers can be used to protect the joint surface from damage.
These threaded products are very prevalent amongst gearbox manufacturers and open gearing. Other common applications for double end, tap end single end, and fully threaded studs are in the wind tower, nuclear power, marine, railway, construction, and a wide variety of special machine building. The diversity of these industries demand that studs be made of all types of nonferrous and other exotic materials.