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Spanners, Sockets and Wrenches.

Types of Spanner

Open ended spanner

These are spanners with a U-shaped opening that fits across two opposing faces of a nut or bolt head. They can be double-ended, with a different-sized opening at each end, but the most versatile spanners have one end open and the other end in a ring – commonly referred to as combination spanners (see ring spanner).

The jaws of the spanner are oriented at an angle of around 15 degrees to the longitudinal axis of the handle. By turning the spanner over at each turn, it gives a greater range of movement in tight spaces.

Ring spanner

So called because the spanner 'rings' (encircles) the whole nut or bolt head completely.

Inside the ring is a twelve-point (Bi-hex) opening that fits over hexagonal nuts or bolt heads. This allows the spanner to fit onto the nut or bolt head at 30 degree intervals – very helpful where space is restricted.

The spanner engages with the nut or bolt head across each end of the flats. This is designed to ensure that there is no danger of ‘rounding off’ the corners of the nut or bolt head

Adjustable wrench (Shifter)

We could equally call this an adjustable spanner, but the name seems to have stuck in the American form.

This is a 'one tool fits all' solution developed to take account of the masses of different nut and bolt sizes.

The worm wheel in the body of the spanner can be turned to adjust the jaws of the spanner to the correct size.

With this type of spanner it is very important that the jaws are adjusted to tightly grip the nut or bolt head. If they are loose, there is a very real danger of rounding off the nut.

A sign of a high quality adjustable wrench is that you can’t wobble the sliding jaw much at all.

A poor quality version is likely to have a fair bit of play. This tends to let the jaws open to a V shape, making damage to the nut or bolt head almost inevitable.

We will take a look later at a special C.K adjustable wrench that has been designed to minimize the risk of rounding off.

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