Screws and Screwing in Metal Work

Screws for holding metal parts together have countersunk, round, or cheese-shaped heads. For sizes below &-in in diameter SCREWS screws cut with the B.S.A. Thread are recommended; and for larger sizes those with British Standard Whitworth threads. Holes through which metal screws have to pass imist be bored to the full size of the screw … Read more


ALL wall switches controlling lights should have a quick-break action, which completes the switching on or off automatically when the knob has been moved part way up or down. This prevents arcing, and burning at the contact points. If a switch spring breaks, replace the switch. Even good switches – and it is false economy … Read more