The Health and Safety Executive completed a major review of legislation in 1992 introducing the Supply of Machinery (Safety) Regulations 1992 and amending the Provision and Use of Work Equipment Regulations 1998 (PUWER 98). The primary objective was to ensure that work equipment, including abrasive wheels, does not give rise to risks to health and safety, regardless of the work equipment’s age, condition or origin. PUWER 98 applies to all workplaces and work situations subject to the Health and Safety at Work Act 1974 (HSW Act).
This brought the provisions of the Abrasive Wheels Regulations 1970 (dealing with the training, competence and appointment of people to mount abrasive wheels) under the amended general requirements of PUWER 98, covering angle grinder training.
The purpose of this blog is to give advice on precautions for the prevention of accidents in the use of abrasive wheels, cut off saw and angle grinder health and safety, in particular the danger of injury resulting from either wheel breakage or contact with a running wheel.
The risk of breakage is inherent in every abrasive wheel. If the number of breakages is to be kept low, the initial care exercised in the design, manufacture and testing by abrasive wheel and machine makers must be coupled with the adoption of safety measures by the users. Accident statistics indicate that nearly half of all accidents involving abrasive wheels are due to an unsafe system of work or operator error.
In relation to abrasive wheels, PUWER 98 requires, among other things, that all machinery is suitable for its intended use and is properly maintained, and that employees, including those using, mounting and managing the operation of abrasive wheels, are fully informed and properly trained in their safe use.
There is no substitute for thorough practical training in all aspects of the mounting and use of abrasive wheels. Our training programs cover :
(a) hazards and risks arising from the use of abrasive wheels and the precautions to be observed;
(b) methods of marking abrasive wheels with their type, size and maximum operating speed;
(c) how to store, handle and transport abrasive wheels;
(d) how to inspect and test abrasive wheels for damage;
(e) the functions of all the components used with abrasive wheels such as flanges, blotters, bushes, nuts etc;
(f) how to assemble abrasive wheels correctly to make sure they are properly balanced and fit to use;
(g) the proper method of dressing an abrasive wheel (removing dulled abrasive or other material from the cutting surface and/or removing material to correct any uneven wear of the wheel);
(h) the correct adjustment of the work rest on pedestal or bench grinding machines;
(i) the use of suitable personal protective equipment, for example eye protection
It is recommended that a record of training in the safe mounting of abrasive wheels is kept, showing the trainee’s name and date of training. These are detailed on the Kentra Training ID cards issued following our Abrasives Wheels training courses.
Summary of operating precautions
Giving that an abrasive wheel is of sound manufacture and mounted on a well-designed machine, safe operation depends largely on proper maintenance and on the treatment to which the wheel is subjected when in use. The following are among the main operating precautions to consider.
Training of operators.
Operators should be properly trained in the safe use of grinding machines, angle grinder health and safety, stihl saw health and safety and /or abrasive wheel operations.
The floor immediately surrounding fixed grinding machines should be maintained in good condition, and free from obstruction. Splash guards should be used when appropriate to prevent the floor from becoming slippery.
Mounting of abrasive wheels should only be done by appropriately trained people
The maximum operating speed marked on the wheel should under no circumstances be exceeded
The wheel guard should always be secured in position and properly adjusted before the wheel is run.
Work rests should be kept adjusted as close as possible to the wheel. Lack of compensation for wheel wear is the main reason for the work rest to be out of adjustment. Work rests should therefore be inspected and adjusted at frequent intervals.
Grinding on the sides of straight-sided wheels used for offhand grinding is dangerous, particularly when they are appreciably worn or when
sudden pressure is applied.
Truing and dressing.
Wheels used for off-hand grinding should be trued frequently to eliminate out-of-balance conditions and to enable the work rest to be
adjusted close to the wheel surface.
Spindles should not be allowed to become overheated due to lack of lubrication.#
Starting new wheels.
New wheels should be run free at normal operating speed for about a minute. Operators and others should stand clear during the trial
Wheels should not be brought to rest by applying pressure to the periphery or face.
Prolonged immersion of a stationary wheel in coolant can throw the wheel out of balance when the machine is started. Before a wheel is stopped the coolant should be turned off, and the wheel run free until it is dry.
Components in the tray should be carefully inspected before grinding, as an oversize piece may damage the wheel or may be projected
Cutting-off and depressed-centre wheels.
The correct wheel for the job, recommended by the wheel manufacturer, should be used. Before mounting, cutting-off wheels should be inspected for possible warping or other defects. A warped wheel should not be used as it may cause excessive vibration, side pressure, or heating and possible wheel breakage. Cutting-off wheels should be mounted only on machines designed for their use. Only the reinforced type should be used on hand-held portable machines. Power should be adequate, otherwise stresses may build up and the wheel may stall and break. Pressure should be applied evenly. Care should be taken to avoid twisting or exerting pressure on the side of the wheel. The workpiece should be rigidly supported and firmly clamped. Lack of rigidity either in the wheel or in the workpiece can lead to wheel breakage.
Wire- or tape-bound cylinder wheels should be worn down to the first tape or group of wires before any are removed. Care should be taken
not to damage the wheel when removing the wires or tape.
Mounted wheels and points.
The overhang should not exceed that appropriate to the speed, size of point and diameter of the mandrel.
Eye protectors should be worn in all dry grinding operations or, alternatively, transparent screens should be fitted to fixed machines to intercept sparks and particles.
To comply with the Personal Protective Equipment Regulations 1992 and other regulations, for example the Control of Substances Hazardous to Health Regulations and the Control of Noise at Work Regulations 2005, appropriate protection must be worn. People who use abrasive wheels on any type of machine are exposed to a number of risks:
(a) Injury to the eyes from flying abrasive and metallic particles,
(b) Inhalation of dust from dry grinding operations (for example petrol-engined cutting-off machines);
(c) Physical injury due to flying wheel fragments or ejected workpieces;
(d) Noise and vibration;
(e) On construction sites there will be a need for head protection as well as for feet and hands in addition to the other precautions mentioned.
Eye protection should conform to the relevant BS EN standard such as BS EN 166 Personal eye protection. Specifications; BS EN 167 Personal eye protection. Optical test methods; and BS EN 168 Personal eye protection. Nonoptical test methods.
Dust protection (face masks) etc should comply with BS EN 149 Respiratory protective devices.
Loose clothing such as ties or coat sleeves are easily drawn in between the wheel and the workpiece and should not be worn. Rags and waste should not be used near a revolving wheel as they may also become entangled.
So back to the question we asked at the beginning of our blog – Who Needs Angle Grinder Training?
Everyone…. every operator of an Abrasive wheel requires at minimum an Awareness training course however, as mentioned earlier, the HSE advises that there is no substitute for thorough practical training in all aspects of Angle Grinder, Cut off saw or Stihl saw training.
There are three different training options which Kentra provide
- Abrasive wheels awareness – a half day awareness course
- Abrasive wheels practical grinding and cutting – for the use of Angle grinders. This course includes a practical training session.
- Abrasive wheels cut off saw – for the use of stihl saw type cut off saw again including a practical training session.
We have course syllabus for each of the separate courses, detailing the coverage and learning outcomes, please do not hesitate to contact us for these details or if you would like to discuss the options available. Here’s a link to our ‘get in touch’ page. We look forward to helping you.