What is the standard for hand screws? What are the hand screws? Hand screw is also a problem that many people are concerned about, it as a processing is not very simple screw products, the use of this screw products is the common sense of the manufacturing industry, it can be seen that its role is huge. Hand screw standards need to consult the business before purchase to have a deeper understanding of this nut product.
Standard of hand screw: main standards and technical parameters 1, nominal diameter: screw design, production, inspection and other recognized diameter. 2, pitch or number of teeth: the distance between two adjacent tooth tops or the number of teeth per inch of length. 3, circular diameter: the maximum average outside diameter measured by the screw. 4. Triangle diameter: the average distance between the top part of the screw triangle and the opposite arc. 5. Bottom aperture: the original aperture before the screw hole is tapped. 6, nominal length: screw design, production, inspection and other recognized length. 7. Damage torque: The minimum torque required for the screw to crack or break. 8, tension resistance: screws in the axial plastic deformation or fracture state required minimum tension. 9. Surface hardness: The average hardness measured by the flat part of the head of the screw surface. 10, core hardness: screw section from the center of about 1/2 radius position measured by the average hardness. 11, carburizing hardening layer depth: the thickness of the hardening layer after the surface carburizing treatment of the screw.
The standard of screws in the general market is more :DIN912(GB70-85) hexagonal cylindrical head screws, Its specifications can be as small as M2(diameter of thread rod, thread length is not limited), such as :M2.5 M3 M4 M5 M6 M8 M10 M12 M14 and so on (length is not limited) By the way, I'm telling you what the screw specification is composed of: it is composed of the length of the screw rod (not including the head), the thread (the distance between the thread and the thread) and the diameter of the screw rod. Let me use the data above for an analogy. For example, the smallest specification M2, its professional standard name is: M2-0.4x5 (M2 is the length of the thread rod,0.4 is the thread pitch,5 is the diameter of the thread rod). Generally, their materials are :4.8, 8.8, 10.9, 12.9, etc. Stainless steel,S04, S16, etc.
