What is thread rolling &thread cutting?

Thread rolling is a mental rolling process used extensively in manufacturing industry to produce screws,bolts and other fasteners.A common thread rolling process,used in industry to manufacture threaded parts,involves forming the threads into the metal of blank by a pressing and rolling action between two die.

Thread cutting is a process for generating a thread.It;s used for the production of threads on the outer space of cylinder or on the inner surface of a bore.Tools used for thread cutting are the thread cutting die,the screws tab or for serial production a precess called cold or hot forming.

What is the difference beteen cut &rolled threads?

Rolled thread,extrued by dies,are stronger than cut threads,made on a lathe or with a hand die,because their grain flows in more than one direction,following the contour of the fastener.It takes a lot more labor to cut threads than to roll them,so it's more costly.Compared to other production methods,rolled thread have improved physical properties.the cold working takes place in the thread rolling process produces an increase in tensile strength and a better surface finish than is achieved with cutting operations,also creats fatigue resistance.