Copper Crush Washers Assortment Kit

This assortment kit contains 330 flat copper washers in 12 metric thread sizes: M5, M6, M8, M10, M12, M14, M16 and M20. Each size is supplied in practical quantities to support repeated use across maintenance cycles. Made from pure copper, the washers are soft, malleable and naturally corrosion-resistant. They measure approximately 1.5 mm thick with inner and outer diameters proportionate to their nominal thread size — for example, an M10 washer has an inner diameter of ~10.5 mm and outer diameter of ~18 mm (exact dimensions vary per size). Their uniform flat profile ensures consistent deformation under torque, forming reliable metal-to-metal seals. These washers are engineered specifically for crush-type sealing applications where controlled plastic deformation is required — such as oil drain plug sealing, fuel line connections, hydraulic fittings and sump plug installations. Copper’s high thermal and electrical conductivity supports stable performance under temperature cycling and vibration. Unlike steel or rubber alternatives, they do not harden or degrade over time when exposed to oils, fuels or moisture. Ideal for automotive workshops, plumbing contractors and mechanical maintenance technicians, this kit supports routine servicing of engines, gearboxes, differentials and industrial fluid systems. The washers are also suitable for electronics grounding applications where low-resistance contact is needed. Packaged in a rigid, transparent plastic storage box with labelled compartments for each size, enabling fast identification and organised access during repair work.