9.1 PULLOUT CALCULATIONS AND BOLT CLAMP LOADS

Screw thread systems are shown with their basic geometries and dimensions in Sec. 5.2.

Engagement of Threads. The length of engagement of a stud end or bolt end E can be stated in terms of the major diameter D of the thread. In general,

• For a steel stud in cast iron or steel, E = 1.50 D.

• For a steel stud in hardened steel or high-strength bronze, E = D.

• For a steel stud in aluminum or magnesium alloys subjected to shock loads, E = 2.00 D + 0.062.

• For a steel stud as described, subjected to normal loads, E = 1.50 D + 0.062.

Load to Break a Threaded Section. For screws or bolts,

where P _b = load to break the screw or bolt, lbf

S = ultimate tensile strength of screw or bolt material, lb/in ²

A _ts = tensile stress area of screw or bolt thread, in ²

NOTE. UNJ round-root threads will develop higher loads and have higher endurance limits.

Tensile Stress Area Calculation. The tensile stress area A _ts of screws and bolts is derived from

where A _ts = tensile stress area, in ²

D = basic major diameter of thread, in

n = number of threads per inch

NOTE. You may select the stress areas...