Thread standards define the shape, dimensions, and tolerances of screw and bolt threads. This category covers metric, inch-based, pipe, and special thread profiles according to ISO, DIN, ANSI, and other standards.
ST threads, standardized under DIN 7970, are self-tapping screw threads designed specifically for sheet metal applications. These threads enable screws to cut their own mating threads into thin sheet materials such as steel, aluminum, and plastic without requiring pre-threaded holes. ST threads feature a sharply angled profile, often 60° or 45°, and a narrow root … Read more
Edison screw threads are the standardized screw bases used in light bulbs and lamp holders worldwide. They are designated with the letter ‘E’, followed by the nominal major diameter in millimeters (e.g., E27 for a 27 mm diameter). These threads provide a secure and reliable electrical connection, ensuring easy installation and removal of bulbs. Edison … Read more
Knuckle threads, standardized under DIN 405, feature a rounded thread profile designed for improved wear resistance and smooth motion in applications subject to high impact and frequent engagement/disengagement. Unlike standard trapezoidal or square threads, knuckle threads have semi-circular crests and roots, making them ideal for low-friction and self-cleaning mechanisms. Knuckle threads are commonly used in … Read more
Buttress threads are asymmetrical thread profiles designed for applications where high loads are applied in one direction. These threads provide high axial load capacity while minimizing friction and wear in the primary loading direction. Unlike symmetrical threads such as Acme or trapezoidal threads, Buttress threads have an angled leading flank (usually 30°) and a nearly … Read more
Square threads are one of the oldest power transmission thread types, designed for maximum efficiency in linear motion applications. Unlike trapezoidal or Acme threads, square threads have perpendicular thread flanks, which result in minimal friction and high efficiency in motion transfer. However, due to manufacturing difficulties and weaker root strength, they have largely been replaced … Read more
