Buttress thread

Buttress thread forms, also known as sawtooth thread forms or breech-lock thread forms. are screw thread profiles with an asymmetric shape, having one square face and the other slanted. They are most commonly used for leadscrews where the load is principally applied in one direction. The asymmetric thread form allows the thread to have low friction and withstand greater loads than other forms in one direction, but at the cost of higher friction and inferior load bearing in the opposite direction. They are typically easier to manufacture than square thread forms but offer higher load capacity than equivalently sized trapezoidal thread forms.

Buttress thread forms, also known as sawtooth thread forms or breech-lock thread forms. are screw thread profiles with an asymmetric shape, having one square face and the other slanted. They are most commonly used for leadscrews where the load is principally applied in one direction. The asymmetric thread form allows the thread to have low friction and withstand greater loads than other forms in one direction, but at the cost of higher friction and inferior load bearing in the opposite direction. They are typically easier to manufacture than square thread forms but offer higher load capacity than equivalently sized trapezoidal thread forms. ===Types=== The image gallery below shows some of the types of buttress threads. File:Buttress thread form.svg|Simple buttress thread form File:ANSI 45-7 Buttress thread form.svg|The ANSI 45°/7° buttress thread form File:British 45-7 buttress thread form.svg|The British 45°/7° buttress thread form File:45-5 buttress thread form.svg|The 45°/5° buttress thread form File:Saw tooth buttress thread form.svg|The 30°/3° German "Sägengewinde" (saw tooth) buttress thread form ===Mechanics=== ==Buttress thread in oil field tubing== In oil field tubing, buttress thread is a pipe thread form designed to provide a tight hydraulic seal. The thread form is similar to that of Acme thread but there are two distinct threaded portions of differing diameters and profiles, the larger having a wedging profile, with a tapered sealing portion in between the larger and smaller diameters. High torque may be transmitted and longitudinal force is transmitted almost parallel to the axis. The thread is about the same strength as standard V threads. ==See also== Leadscrew Trapezoidal thread form ==References== ===Bibliography===

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