bolts

Bolt are cylindrical (as opposed to conical) threaded fasteners that pass through the work pieces and are held in places by a nut or a threaded hole on the other side. This is a very common way of holding together temporary and permanent constructions. An unthreaded hole is known as a clear hole. The thread on a bolt sometimes occupies only part of the shaft, the remainder of the shaft being clear; if the thread continues up to the head it is known as a 'set'. China is one of the leading countries of bolts.