Straight knurled screw Thumb screw Step copper screw M5 M6 M8 M10

Flat washers are usually thin pieces of various shapes used to reduce friction, prevent leakage, isolate, and prevent loosening or dispersion of pressure. Many materials and structures contain this component, which is used to perform various similar functions. Due to the material and process limitations of Threaded fastener, the bearing surface of bolts and other fasteners is not large, so in order to reduce the pressure stress of the bearing surface and protect the surface of the connected parts, gaskets are used. To prevent the loosening of the connecting pair, anti loosening spring washers, multi tooth lock washers, round nut stop washers, and saddle, waveform, and conical elastic washers are used.

As a standard component, it should have its own universal specifications for hexagonal nuts. Commonly used standards include GB52, GB6170, GB6172, and DIN934. The main difference between them is that the thickness of GB6170 is thicker than that of GB52, GB6172, and DIN934, commonly known as thick nuts. In addition, there is a difference in the opposite side. In the M8 nut series, the opposite sides of DIN934, GB6170, and GB6172 are all 13MM smaller than the 14MM opposite side of GB52. The M10 nut series has a 17MM opposite side of DIN934 and GB52, which is 1MM larger than the GB6170 and GB6172. The M12 nut series has a 19MM opposite side of DIN934 and GB52, which is 1MM larger than the 18MM opposite side of GB6170 and GB6172. For M14 nuts, the opposite side of DIN934 and GB52 is 22MM larger than that of GB6170 and GB6172, which is 21MM larger. In addition, the M22 nut has a 32mm across edge for DIN934 and GB52, which is 2MM smaller than the 34mm across edge for GB6170 and GB6172. (GB6170 and GB6172 have the same width across the edges except for their different thicknesses) Other specifications can be universal without considering thickness.

"Thread code editing broadcast
Coarse teeth series UNC
Fine Teeth Series UNF
Ultra fine teeth series UNEF
Fixed pitch series UN
Annotation Method Editing Broadcast
Labeling method: Thread diameter - Number of teeth per inch series code - Example of accuracy level:
Coarse Teeth Series 3/8-16 UNC-2A
Fine Teeth Series 3/8-24 UNF-2A
Extra Fine Teeth Series 3/8-32 UNEF-2A
Fixed pitch series 3/8-20 UN-2A
The first digit, 3/8, represents the outer diameter of the thread in inches. To convert to metric units, mm must be multiplied by 25.4, which is 3/8 × 25.4=9.525mm; The second and third digits 16, 24, 32, and 20 represent the number of teeth per inch (teeth on a length of 25.4mm); The text codes UNC, UNF, UNEF, UN after the third digit represent the series codes, and the last two digits 2A represent the accuracy level. UNC: Unified coarse thread"

1. The twisted screw should be considered based on the actual inner diameter of the barrel, and the outer diameter deviation of the new screw should be given according to the normal gap with the barrel for manufacturing. 2. After the thread surface with reduced diameter of wear screw is treated, wear-resistant tungsten carbide alloy is Thermal spraying, and then grinded to size. 3. Weld wear-resistant tungsten carbide alloy on the threaded part of the worn screw. Weld 1-2 mm thick according to the degree of screw wear, and then grind and process the screw to its size. This wear-resistant tungsten carbide alloy is composed of materials such as C, Cr, Vi, Co, W, and B, which increases the wear and corrosion resistance of the screw. 4. Repair the bottom diameter of the screw using electroplating hard chromium treatment method. Chromium is also a wear-resistant and corrosion-resistant metal, but the hard chromium layer is relatively easy to fall off.