When an aluminumrivet is upset against a softer material, a washer must be used under the upset head to prevent eruption of the softer material.
当一个铝铆钉的镦头形成在较软的材料一边时，必需在铆钉镦头下使用垫片以防止较软材料胀裂。
2
Precision spring(compression/tension/torsion/special-shape/battery spring), USB stainless clockwork spring, copper, iron and aluminumrivet, nail claw/claw pearl, and toy axle.