Abrasive Wheels Training Certificate Work Rest Adjustment and Operating Techniques 1 — Questions and Answers
Question 1: What is the maximum recommended gap between the work rest and an abrasive wheel on a bench or pedestal grinder?
- 1 mm
- 2 mm
- 3 mm (Correct answer)
- 6 mm
Correct answer: 3 mm
HSE guidance states the work rest must be adjusted to within 3 mm (approximately 1/8 inch) of the wheel to prevent the workpiece from being drawn into the gap.
Question 2: When should the work rest on a grinding machine be re-adjusted?
- Only when the wheel is replaced
- Whenever the gap exceeds the safe limit due to wheel wear (Correct answer)
- Once per week regardless of wheel condition
- Only when instructed by a supervisor
Correct answer: Whenever the gap exceeds the safe limit due to wheel wear
As the abrasive wheel wears down during use its diameter decreases, increasing the gap between wheel and rest, so re-adjustment is required whenever the safe limit is exceeded.
Question 3: At what height should the work rest be set relative to the centre of the abrasive wheel?
- Significantly below centre
- At or slightly above centre (Correct answer)
- Exactly at centre height only
- Significantly above centre
Correct answer: At or slightly above centre
Setting the rest at or slightly above the wheel centreline ensures any downward grinding force directs the workpiece onto the rest rather than trapping it between the wheel and the rest.
Question 4: What is the primary reason for keeping the work rest as close to the abrasive wheel as possible?
- To improve grinding speed and efficiency
- To prevent the workpiece from being drawn between the wheel and rest (Correct answer)
- To reduce heat generation during grinding
- To extend the working life of the abrasive wheel
Correct answer: To prevent the workpiece from being drawn between the wheel and rest
If the gap is too large, a workpiece can be snatched and violently pulled into the gap, causing serious injury to the operator or shattering the wheel.
Question 5: Who should carry out adjustments to the work rest on a pedestal grinder?
- Any trained operator at the start of each shift
- Only an appointed, competent person (Correct answer)
- The operator whenever they notice the gap has increased
- The manufacturer's representative only
Correct answer: Only an appointed, competent person
Under UK regulations, work rest adjustments must be carried out by an appointed, competent person to ensure they are set correctly and safely.
Question 6: What must be done BEFORE adjusting the work rest on a grinding machine?
- Put on additional eye protection
- Isolate and lock off the machine to prevent accidental start-up (Correct answer)
- Inform all workers in the surrounding area
- Confirm the wheel speed rating on the spindle
Correct answer: Isolate and lock off the machine to prevent accidental start-up
The machine must be isolated and locked off before any adjustment to prevent accidental start-up, which could cause severe injury to the person making the adjustment.
Question 7: After re-adjusting the work rest following wheel wear, what must be verified before resuming work?
- The wheel speed matches the machine's rated speed
- The gap between the work rest and wheel is within the safe maximum (Correct answer)
- The coolant reservoir is adequately topped up
- The operator's PPE is in serviceable condition
Correct answer: The gap between the work rest and wheel is within the safe maximum
After adjustment, the gap between the work rest and wheel must be measured and confirmed to be within the maximum safe limit before the machine is returned to use.
Abrasive Wheels Training Certificate Work Rest Adjustment and Operating Techniques 1
What is the maximum recommended gap between the work rest and an abrasive wheel on a bench or pedestal grinder?