Spanners come in various forms and are used to tighten and loosen nuts and bolts. Essential to any tool kit, spanners are available in metric and imperial sizes. Here are some useful tips on using spanners:
- Never force a spanner onto the head of a bolt or nut as this can damage the gripping edge of the spanner.
- Spanners are designed to be used with a reasonable amount of force, but be careful not to apply excessive force as this can result in the spanner slipping off the head of the bolt or nut causing injury.
- Never hit the handle of a spanner with a hammer to force movement.
The open-ended ‘C’ spanner is the most common type, and may have a single or double end. Each head of a double open-end spanner is designed to fit nuts and bolts of different sizes. The head has its jaws offset by about 15 degrees from the run of the shaft. This makes it easier to operate in tight spaces. Open-ended spanners can be purchased individually or in sets made up of just a few spanners or a large selection.
As the name implies, the ring spanner usually has a completely enclosed head and may have 6 or 12 notches within the ring. A 12-notch spanner engages upon the corners of the nut and can engage both hexagonal and square bolts. A 6 notch spanner is normally shaped to fit against all 6 sides of hexagon nuts, this ensures a very tight fit and can allow considerable force to be applied. Ring spanners are stronger than the open-ended type. Ring spanners can also be purchased individually or in sets.
The most common version has its jaws set at an angle of 15 degrees to the shaft. A worm screw is situated close to the jaws of the spanner, which makes adjusting its size with the finger and thumb of the holding hand easier.
Immersion heater box spanner
Large box spanner designed specifically for immersion heaters. Turned with a T-bar or tommy bar, which may be part of the design or separate.
Tommy bar or T-bar
A short metal bar used to turn a box spanner.
Made of a tough steel alloy, socket sets comprise of a number of steel sockets in different sizes that attach to a ratcheted handle. The socket fits over the head of the bolt or the nut of corresponding size and by adjusting the ratchet control can tighten or loosen the nut or bolt.
These are simple hexagonal shaped rods with a right-angle bend designed to engage into the head of a screw, which has a hexagonal shaped recess in its head – this is a very common screw found in many modern domestic appliances. Allen keys are also available in sets of metric and imperial sizes.