Hand Threading and Reaming - Types of Screw Thread
Video
Thread form refers to the profile of a screw thread. Thread standards that define thread form, series, class, allowance, tolerance and designation are usually issued by thread form.
 
Metric V-Thread
Metric threads are used in a wide variety of applications. They are commonly used in machine tools, automobiles, and furniture. Metric threads are also used in a variety of other applications, such as medical devices, aerospace, and electronics.

Use

  • General fasteners

  • Bolts and nuts
 
British Standard Whitworth (BSW) thread
BSW is an imperial-unit-based screw thread standard, devised and specified by Joseph Whitworth in 1841 and later adopted as a British Standard. It was the world's first national screw thread standard, and is the basis for many other standards, such as BSF, BSP, BSCon, and BSCopper.
Use
  • General fasteners
  • Bolts and nuts
  • Pipe fittings
 
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.
Use
  • Bench vices
  • Machine vices
  • Jacks
  • Building props
  • Where great force must be resisted in one direction only
 
Square thread
Square thread form is a common screw thread profile, used in high load applications such as leadscrews and jackscrews. It gets its name from the square cross-section of the thread. It is the lowest friction and most efficient thread form, but it is difficult to fabricate.
Use
  • Ideal for power transmission
  • Cross and compound slide on lathe
  • Table moment on milling machine
 
ACME thread
Acme threads are screw threads with a trapezoidal form factor that are comparatively easier to manufacture than square threads and provide high accuracy. As a result, these threads are used for high-precision applications such as lead screw drives for CNC machines and other power transmission systems.
Use
  • Where backlash and play must be reduced
  • Lead screw on lathe for screw thread cutting