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A grinder spins a disc or wheel of bonded abrasive to grind or cut metal. In this factsheet, the terms “disc” and “wheel” are used interchangeably.
While this guidance has not been updated to reflect current work health and safety legislation (the Health and Safety at Work Act 2015 and regulations), it may still contain relevant information and practices to keep workers and others healthy and safe.
Please read this guidance in conjunction with all relevant industry standards that apply to you as a PCBU. This guidance will be progressively reviewed and either updated, replaced with other guidance, or revoked.
An angle grinder is a hand-held tool carried to the work, with the disc secured at an angle to the body of the grinder.
An offhand grinder, which may be fixed to a bench or a pedestal, is usually fitted with one or two abrasive discs revolving at right angles to the spindle turned by a motor. Figure 2 shows a wire wheel on the left, and an abrasive wheel on the right.
Abrasive discs may be replaced by wire brushes for cleaning, or cloth buffs for polishing. Angle grinders used to cut tiles may be fitted with a diamond-tipped blade.
Figure 1: Angle grinder
Figure 2: Bench grinder
- Entanglement with turning wheel or disc
- Contact with uncontrolled grinder
- Electrical current
- Sparks & hot metal
- Fumes & toxic dust
- Slips, trips & falls
- Accidental starting causing projectiles
Personal protective equipment (PPE)
- Ear protection
- Eye protection
- Face protection
- Hand protection
- Foot protection
- Respiratory protection
Entanglement with turning wheel or disc
- Crushing to body parts
- Cuts to body parts
- Scalping if hair is caught
- TIE BACK long hair and beards.
- WEAR tight fitting clothes, especially tight fitting sleeves, without long ties.
- DO NOT WEAR jewellery.
Loose clothing, long hair, or jewellery can wrap around spinning wheels.
Projectiles from incorrectly used wheels or discs
- Can pierce, causing injury or death
- USE the wheel or disc as per manufacturer’s instructions.
- DO NOT spin discs faster than specified.
- NEVER use a worn disc from a large grinder in a small grinder, where they will spin faster.
Users must know whether discs are designed to be used on the side or on the edge. Working against the wrong surface will damage the disc. Centrifugal forces may break the bonding materials apart, with broken discs forming projectiles. These projectiles have caused serious harm and death.
Projectiles from damaged discs
- Can pierce, causing injury or death
- KEEP wheels and discs stored correctly to avoid moisture and impact damage.
- FOLLOW INSTRUCTIONS when a wheel is allowed to be used wet.
- DISPOSE of damaged discs or wheels.
- WATCH YOUR SPEED – read the label and match the speed of wheel or disc to the grinder.
- SIZE MATTERS – match the wheel or disc to the grinder.
- APPLY the “ring test” before fitting wheels.
- MINIMISE the gap between tool rests and abrasive wheels.
- ANTICIPATE movement of the workpiece when using an angle grinder.
Discs and wheels MUST avoid moisture damage. Workpieces and hand-held grinders move unexpectedly. Workpieces may jam against wheels or discs, breaking them and stopping them from spinning freely, resulting in damage to the disc. Discs and wheels of the wrong size may fly apart by turning at the wrong speed.
Projectiles from wire breaking off brushes
- Wire bristles can contact or pierce eyes
- PUT eye shields in place, or WEAR face shields.
- GLOVES MAY be worn, but NEVER close to a turning wheel or brush.
Wi￼re breaks from brushes and is thrown towards the operator.
Projectiles from thrown workpieces
- Serious harm – contact, impact or piercing injuries
- SECURE workpieces held against abrasive wheels or wire wheels.
- USE A JIG if clamps or pliers will not secure the workpiece.
- WEAR safety footwear.
Loosely held workpieces may be thrown from the wheel or disc.
Contact with an uncontrolled angle grinder
- Body parts cut by contact with abrasive discs
- ENSURE that the hold-to-run control shuts off power when it is released.
- SECURELY HOLD the angle grinder with both hands at all times when in contact with the workpiece.
- ANTICIPATE movement of the workpiece causing kickback.
When an angle grinder is put down before the disc stops turning it can spin out of control. There may be contact when an angle grinder kicks back. Discs MUST be securely mounted within the flanges of the grinder. Proper mounting hardware MUST be fitted at the spindle of the grinder and the arbour of the disc. For hand-held grinders, guards MUST be fixed between the wheel and the operator. The handle MUST be screwed in securely on the appropriate side of the wheel.
Other (non-mechanical) hazards
- Electrocution causing injury or death
- ONLY USE grinders in dry conditions.
- Regularly INSPECT and TEST grinders to ensure they meet safe electrical standards.
- USE a residual current device (RCD) outside.
Electrical hazards may make metal components live, especially when wet.
- Hearing damage or loss
- REDUCE noise levels by working within noise barriers.
- ASSESS noise levels.
- ARRANGE hearing screenings.
- ALWAYS WEAR hearing protection.
A safe level of noise over an eight hour day is 85dB(A). A grinder may exceed this noise intensity. Noisy angle grinders can also interfere with spoken communication.
Sparks and hot metal
- Fire or explosion – potential burns injuries
- Property damage
- SET spark arrestors in place to contain sparks as much as possible.
- GET a hot work permit for any work near flammable material.
- CLEAN UP combustible dust from grinding.
Sparks and hot metal may ignite combustible material.
Fumes and toxic dust – fire and explosion
- Harm to breathing and lung damage
- EXTRACT dust by ventilation.
- CONTAIN and CONTROL metal dust.
- CLEAN UP surface dust as soon as possible.
- Vacuum cleaners MUST be designed for cleaning metal dust.
- DO NOT blow metal dust with compressed air – this will only move it elsewhere.
- ALWAYS USE respiratory protection.
Slips trips and falls
- KEEP up-to-date housekeeping procedures.
- KEEP the work area clear of slip and trip hazards.
Task – Maintenance, cleaning & repairs
Accidental starting causing projectiles
- Potential piercing injuries
- Eye irritation or damage
- LOCK-OUT ALL power supplies before maintenance, cleaning and repairs.
- Keep tools well maintained
- Test abrasive wheels BEFORE mounting.
- Correctly adjust guards.
Abrasive wheels for fixed grinders MUST be tested before mounting by hitting with a piece of wood. If the wheel makes a ringing sound it is safe to use, otherwise it is probably cracked and MUST be discarded. Newly fitted abrasive wheels MUST be run for a minute or so to ensure that they do not fly apart. The path of any projectile MUST be clear of people. For fixed bench or pedestal grinders, tool rests, tongue guards and eye shields MUST be in place.
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