When using a vice, there are a few rules that should be followed in order to keep the vice in working order and to protect your workpiece from damage.
Always clamp the workpiece securely, ensuring that the full clamping surface of the jaws supports the object.
If clamping a long workpiece, then support the end of the object with an adjustable stand, box, or table, in order to avoid putting any extra strain on the vice.
Do not weld the base of a vice to any metal.
Never use welding or brazing to repair a vice. If a vice has any cracks or damage to it then do not use it.
Do not use a light-duty vice to clamp a heavy object. Always use a vice which is designed to hold the weight of the object you wish to work on.
Do not add an extension onto the vice handle in an attempt to increase the clamping pressure. The extra pressure of an extension could cause the handle to bend or the vice to break.
Never hammer any parts of the vice, as this will only damage it. The only exception is if a vice has a fitted anvil, then hammering on this section is permitted. Engineer’s and multi-purpose vices tend to have fitted anvils on their bodies which allow for the hammering and shaping of metal objects.