There are four main methods of joining metals:
- mechanical—e.g. bolts, nails, screws, and hot and cold rivets;
- welding; and
- Nails and tacks are used in thin materials, such as metal-sheet cladding, and involve a rigid fixture. They are generally of steel, but be aware of metal compatibility. A variation is railroad spikes, which are large nails with asymmetrical heads used for fixing railway lines to lumber sleepers.
- Screws are threaded fasteners, often tapered, with a head which has a fixture or slot that allows the screw to be rotated. The helical arrangement of the thread drives it into the material. Screws can usually be withdrawn and reused.
The main types of screw used for ...