JIS B 1258 (L):2012 Flat Washer for screw-and-washer assemblies is intended for pre-assembled fasteners where the washer is combined with the screw. This arrangement reduces the number of loose parts on site, prevents washer loss, and improves assembly efficiency in volume production.
It is commonly used in electrical equipment, home appliances, light machinery, instrument housings, and automated assembly lines. When used with the matching screw, the washer provides a flat bearing surface during tightening, protects the connected part, and improves clamping-force distribution.
Corresponding dimensions and surface treatments can be selected according to screw size, assembly space, and corrosion-resistance needs, supporting reliable feeding in high-speed production and stable performance during maintenance disassembly.

Dimensions unit: mm
| Nominal diameter | 2 | 2.5 | 3 | 3.5 | 4 | 5 | 6 | 8 | 10 | 12 | |
| d | Min.=Nominal | 1.75 | 2.25 | 2.75 | 3.2 | 3.6 | 4.55 | 5.5 | 7.4 | 9.3 | 11 |
| Max. | 1.85 | 2.35 | 2.85 | 3.32 | 3.72 | 4.67 | 5.62 | 7.55 | 9.52 | 11.27 | |
| dc | Max.=Nominal | 6 | 8 | 9 | 11 | 12 | 15 | 18 | 24 | 30 | 37 |
| Min. | 5.7 | 7.64 | 8.64 | 10.57 | 11.57 | 14.57 | 17.57 | 23.48 | 29.48 | 36.38 | |
| h | Nominal | 0.6 | 0.6 | 0.8 | 0.8 | 1 | 1 | 1.6 | 2 | 2.5 | 3 |
| Max. | 0.65 | 0.65 | 0.85 | 0.85 | 1.06 | 1.06 | 1.68 | 2.09 | 2.6 | 3.11 | |
| Min. | 0.55 | 0.55 | 0.75 | 0.75 | 0.94 | 0.94 | 1.52 | 1.91 | 2.4 | 2.89 | |
ABOUT US
Better Fastener is a professional fastener enterprise specializing in the manufacturing of steel washers, stainless steel washers, spring washers and sealingwashers. Founded in 2001 as a washer factory, the company expanded into a comprehensive enterprise integrating washers, nuts, bolts, spring nuts and other fastener products in 2010.
The company positions itself as a provider of comprehensive one-stop services for customers, relying on technological R&D, industrial investment and trade distribution.
With an experienced professional team and a sound sales network, Better Fastener has achieved excellent sales performance in both domestic and foreign markets,and has grown into one of the competitive manufacturers and suppliers in China's industrial fastener industry.
Better Fastener is committed to becoming a trusted fastener supplier for customers with reliable product quality, reasonable prices and on-time delivery
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