can square thread screw rods can hold high tensile strength.how the maximum tensile strength can be calculated.whats the design procedure for that type of situations.
The machinery handbook lists types of threads & characteristics. For a thread and nut to exert longditudinal force equally in two directions, an acme (square) thread is best. If thrust is uni-directional, a butress thread may be superior. Always consult reference before design.
Tuff question without knowing what you are trying to do. I designed a puller one time and first used a fine pitch screw, thought was more threads the stronger it would be. The problem was repeated use and very high stress. After rebuilding the puller for the 3rd time, I switched to a Acme thread,(square thread) and never had to rebuild that puller ever again.
But if your application is straight holding power, it's not a fuction of the thread, but of the screw material. Spec out a grade 8 bolt and the correct torque and you will be fine.
__________________
Be careful of what you wish for .....
The tensile strength is very much a function of thread form. The old square thread is probably the worst due to stress raiser at the small root radius. You should look into a modified rounded square thread especially one produced by a thread rolling process - which is much preferred over cutting also in avoiding stress concentration.
Screw Rods
Re: Screw Rods
