Frequently asked questions

The short answer is that it is possible under certain conditions, but only on manual lathes. It should never be used at numerically controlled (NC) and computer numerically controlled (CNC) lathes.             

Every year there are serious accidents involving the use of emery cloth on metalworking lathes, resulting in injuries such as lacerations, dislocations, broken bones, amputations and occasionally death.

Most accidents happen when each end of a strip of emery cloth is held in separate hands and passed around the back of the component. Unless the cloth is held taut it can lap back on itself causing the cloth to be ‘snatched’ and wrapped round the rotating component. If the cloth is wrapped around the fingers to give a tight grip, then a serious injury is the likely result.

Gloves have been worn in a significant number of such accidents and increase the risk of entanglement.

For these reasons the application of emery cloth, held directly by hand, should always be avoided.

The application of emery cloth should be risk assessed and the first step is to ask yourself do we absolutely need to use it?

The use of improved tooling, higher specification machine tools and dedicated polishing, honing, linishing or grinding machines are ways of avoiding the need for its use.

If the use of emery cloth is justified then you must use a method that ensures the operator’s hands are clear of the rotating parts.

Emery cloth should only be applied either using a tool post or using a backing board or similar hand held device.

Further information

• Accidents at metalworking lathes using emery cloth

Exposure to metalworking fluids can cause; irritation of the skin/dermatitis, occupational asthma, bronchitis, irritation of the upper respiratory tract, breathing difficulties or, rarely, a more serious lung disease called extrinsic allergic alveolitis (EAA).

Control of Substances Hazardous to Health Regulations (COSHH) requires exposure to metalworking fluids by inhalation, ingestion or skin contact to be prevented where reasonably practicable, or failing that, adequately controlled.

• HSE COSHH website
• e - COSHH essentials metalworking fluids guidance sheets

You should:

• carry out a suitable and sufficient risk assessment – HSE’s self-assessment questionnaire will help you do this;
• maintain fluid quality and control bacterial contamination of fluids;
• minimise skin exposure to fluids;
• prevent or control airborne mists; and
• where there is exposure to fluid or mist, carry out health surveillance.

To achieve the necessary control and risk reduction, among other actions, you will need to:

• check and maintain exposure control measures, such as enclosures and local exhaust ventilation;
• check levels of bacterial contamination using dip slides, or other means of measuring the level of bacterial activity, in both metalworking and associated fluids eg in washing machines, and act on the readings obtained in line with your risk assessment;
• ensure that, as a minimum, a responsible person carries out the required health surveillance;
• conduct asthma health checks
• refer anyone affected by exposure to a competent occupational health professional;
• take prompt action after any diagnosis of ill health to identify the likely cause and ensure it is prevented or adequately controlled; and
• keep workers informed of all findings.
• Working safely with metalworking fluids: A guide for employees

Further information

• Metalworking fluids website

The use of compressed air to remove swarf, dust and fluids from machined components presents a number of risks to both the health and safety of those involved.

There is a risk of compressed air entering the operator's bloodstream, which can result in death.

Eye injury including blindness can occur if dust particles or swarf bounce back at the operator.

Droplets of metalworking fluid can be absorbed by operator clothing and eventually reach the skin. This can result in dermatitis, especially on the hands and arms lower torso.

Photo showing MWF on clothing of worker using compressed air to clean machined components

The use of compressed air may also increase metalworking fluid mist levels in the area around the machine. Metalworking fluid mist is a known cause of respiratory ill health including asthma.

Noise levels are normally high and there is a significant risk of permanent hearing damage from prolonged exposure. Hearing loss can never be restored.

A number of precautions can be taken to reduce the risks and should form part of the risk assessment required for this activity:

• Identify alternative methods of carrying out these tasks, such as the use of vacuum equipment, absorbent materials, swarf hooks and brushes. The Blowchip system is an option on enclosed CNC machines with automatic tool changers.
• Blow down components in an extracted enclosure. This could be the machine if it is enclosed and fitted with an effective extraction system.
• Reduce the exit pressure of the compressed air to as low a level as possible (As a guide some countries have set a maximum level of 30 psi at the point of exit from the nozzle). Gauges are commercially available for testing this exit pressure.
• Consider using air nozzles which have been designed with noise reduction in mind.
• Increase the length of the air gun.
• Provide a shield on the air gun to reduce splash back.
• Provide appropriate training, personal protective equipment, supervision and health surveillance.
• It is a myth that only a noisy compressed air system is effective. Advances in compressed air technology mean that modern systems, if well maintained, can be just as effective producing less noise and using less energy.