Abrasive Wheels Training Certificate Safe Mounting & Dressing Procedures

Question 1

Under PUWER 1998, who is authorised to mount abrasive wheels in the UK?

Accepted Answer

Only a person who has received adequate instruction and training — an 'appointed person' designated by the employer

Answer

Any employee who has used an angle grinder before

Answer

Only a qualified mechanical engineer

Answer

Any person over 18 years of age

Question 2

What checks must be made before mounting an abrasive wheel?

Accepted Answer

Ring test, visual inspection for cracks/damage, check wheel specification matches machine speed rating, check bore size matches spindle

Answer

Visual inspection only

Answer

Check the expiry date on the wheel packaging only

Answer

Only verify the wheel diameter is correct

Question 3

What is the purpose of blotting paper (compressible washers) between the wheel flanges and the abrasive wheel?

Accepted Answer

To distribute clamping pressure evenly across the wheel face, preventing stress concentration and cracking when flanges are tightened

Answer

To prevent the wheel from loosening due to vibration during use

Answer

To provide electrical insulation between the wheel and machine

Answer

To absorb coolant and prevent it reaching the spindle bearing

Question 4

How should the flanges (clamping plates) that retain an abrasive wheel be sized?

Accepted Answer

Each flange must be at least one-third of the wheel diameter and of equal size; the recessed face must bear on the wheel

Answer

Flanges may be any size provided the wheel does not slip

Answer

Only the outer flange needs to be at least one-third diameter; the inner flange can be smaller

Answer

Flanges must be exactly equal to the wheel diameter to provide full face support

Question 5

In which direction should the flange nut be tightened on a right-hand grinding spindle?

Accepted Answer

Clockwise (right-hand thread) — the grinding reaction torque self-tightens a standard right-hand thread

Answer

Anti-clockwise — the wheel must be tightened against the direction of rotation

Answer

Direction does not matter as the nut is locked with a split pin

Answer

The nut should be left slightly loose to allow wheel expansion during use

Question 6

What is the maximum permissible gap between the abrasive wheel and the work rest on a bench grinder?

Accepted Answer

3mm (approximately 1/8 inch) to prevent the workpiece being drawn between the wheel and rest

Answer

No more than 10mm to allow large workpieces to be positioned

Answer

5mm is acceptable for wheels below 200mm diameter

Answer

There is no standard for work rest gap — it is operator preference