Abrasive Wheels Training Certificate Hazards of Abrasive Wheels 2

Question 1

What noise hazard does angle grinder use present, and what control is required?

Accepted Answer

Noise levels typically 95–110 dB(A), exceeding the UK upper exposure action value of 85 dB(A); hearing protection and exposure time limits are required

Answer

Angle grinders typically generate 95–110 dB(A) at the operator's ear. Under the Control of Noise at Work Regulations 2005, the upper exposure action value is 85 dB(A) (8-hour TWA). Above 85 dB(A), hearing protection is mandatory and exposure must be reduced. Above 87 dB(A) peak, hearing protection must keep exposure below the exposure limit value.

Question 2

What is the hazard of 'wheel loading' on an abrasive wheel?

Accepted Answer

The pores between grains become clogged with workpiece material, reducing cutting efficiency, increasing heat build-up, and risking wheel cracking

Answer

Wheel loading occurs when soft or ductile materials (aluminium, copper) clog the pores between abrasive grains. The clogged wheel cuts poorly, generates excessive heat (which can affect the bond integrity), and may cause vibration. A loaded wheel may need redressing or replacement. The heat from a loaded wheel can also affect the workpiece temper.

Question 3

What is the hazard of 'wheel glazing' during bench grinding?

Accepted Answer

Abrasive grains become flattened and polished rather than breaking away, producing a smooth wheel surface that generates excessive heat without cutting

Answer

Glazing occurs with hard-grade wheels on soft workpieces — the soft material wears the grains smooth rather than fracturing them to expose new sharp edges. The glazed wheel heats the workpiece without effectively cutting, causing burn marks and possible thermal stress. Dressing the wheel removes the glazed surface layer.

Question 4

Why is using an angle grinder without a guard particularly dangerous?

Accepted Answer

The guard provides direct protection from wheel fragments if the disc bursts, and prevents contact with the rotating disc during operation

Answer

The grinding disc guard performs two critical functions: it deflects wheel fragments away from the operator if the disc bursts (fragment velocities can be lethal), and it physically prevents accidental contact with the rotating disc. Removing the guard eliminates both protections simultaneously and is a serious safety violation under PUWER.

Question 5

What manual handling hazard is associated with heavy abrasive wheels and angle grinders?

Accepted Answer

Musculoskeletal injury from sustained awkward postures, repetitive use, and holding the weight of the grinder, especially overhead or at arm's length

Answer

Angle grinders weigh 2–5 kg and are often used in sustained awkward postures — overhead, at arm's length, or in confined spaces. Sustained gripping against reaction torque, vibration, and weight causes upper limb musculoskeletal disorders. Pre-planning work positioning to minimise awkward postures reduces this risk.

Abrasive Wheels Practice Test

Abrasive Wheels Practice Test

Abrasive Wheels Training Certificate Hazards of Abrasive Wheels 2