Fasteners & hardware

Simple as they look, screws and bolts cause trouble when a batch arrives in the wrong grade. Give the diameter, length, thread pitch, head style and drive type, and the material or property class, whether mild steel, zinc-plated or stainless, for the environment involved. Nuts and washers should match the bolt specification. For anchors, name the base material, whether concrete, brick or hollow block, and the load; structural fixings should be checked by a qualified engineer.