Abrasive Wheels Training Certificate Safe Mounting & Dressing Procedures 2 — Questions and Answers
Question 1: What is 'wheel dressing' and what tool is used for it?
- Restoring the wheel's cutting face by removing glazed, loaded, or out-of-true abrasive material using a diamond dresser or star-wheel dresser (Correct answer)
- Cleaning the wheel surface with a wire brush
- Applying a coolant coating to the wheel face
- Balancing the wheel on the spindle after mounting
Correct answer: Restoring the wheel's cutting face by removing glazed, loaded, or out-of-true abrasive material using a diamond dresser or star-wheel dresser
Wheel dressing restores the wheel's cutting face: it removes glazed or loaded grains to expose fresh sharp abrasive, corrects out-of-roundness, and re-profiles the wheel face. Diamond dressers (single-point, multi-point, or roller) and star-wheel (Huntington) dressers are the standard tools. Regular dressing maintains cutting efficiency and reduces heat.
Question 2: What is the correct technique for using a single-point diamond dresser on a bench grinder?
- Present the diamond at a 10–15 degree angle to the wheel face, traverse across the face with a slow, steady movement, using light cuts of 0.02–0.05mm per pass (Correct answer)
- Plunge the diamond into the wheel face and traverse rapidly
- Apply maximum downward force for fastest dressing
- Only dress the centre of the wheel face where glazing is worst
Correct answer: Present the diamond at a 10–15 degree angle to the wheel face, traverse across the face with a slow, steady movement, using light cuts of 0.02–0.05mm per pass
The diamond dresser must be presented at 10–15 degrees (not perpendicular, to prevent chattering) and traversed slowly across the full wheel face. Light cuts (0.02–0.05mm) prevent overloading the diamond. Too fast a traverse leaves a coarse thread-like surface; too deep a cut can damage the diamond or crack the wheel.
Question 3: What personal protective equipment is required when dressing an abrasive wheel?
- Safety glasses or goggles (not just spectacles), face shield, and hearing protection; leather gloves are NOT recommended as they reduce dexterity (Correct answer)
- Only hearing protection — dressing produces little abrasive dust
- Standard spectacles provide adequate eye protection for dressing
- Face shield only — hearing protection is not required during brief dressing operations
Correct answer: Safety glasses or goggles (not just spectacles), face shield, and hearing protection; leather gloves are NOT recommended as they reduce dexterity
Wheel dressing ejects fine abrasive particles and metal fragments at high velocity. Safety glasses or goggles with side protection are mandatory; a face shield provides additional full-face protection. Hearing protection addresses the high-frequency grinding noise. Leather gloves reduce dexterity and are generally not recommended — the hands should be kept well clear of the wheel.
Question 4: After dressing a bench grinder wheel, what adjustment must be made to the machine?
- The work rest must be readjusted to maintain the maximum 3mm gap, as dressing reduces the wheel diameter (Correct answer)
- Only the spark arrestor position needs adjustment
- No adjustments are needed after dressing — the wheel diameter change is negligible
- The guard must be replaced with a new one each time the wheel is dressed
Correct answer: The work rest must be readjusted to maintain the maximum 3mm gap, as dressing reduces the wheel diameter
Each dressing operation reduces the wheel diameter. The work rest gap must be readjusted after dressing to maintain the maximum 3mm clearance. Additionally, the wheel guard's tongue (spark deflector) may need adjustment to maintain its correct position relative to the reduced wheel diameter.
Question 5: What is the minimum time a newly mounted abrasive wheel should be run before it is used for work?
- At least 1 minute at full speed with the guard in place and no one in the burst danger zone, to detect any defects before use (Correct answer)
- 30 seconds is sufficient for all wheel sizes
- No run-in period is required if the ring test was conducted
- 5 minutes for wheels over 200mm diameter only
Correct answer: At least 1 minute at full speed with the guard in place and no one in the burst danger zone, to detect any defects before use
A new or freshly mounted wheel must be run at operating speed for at least 1 minute (some standards specify longer for larger wheels) before use, with the guard in place and personnel standing clear of the danger zone. This allows any mounting defect or latent crack to manifest before the wheel contacts a workpiece.
Question 6: What is the correct procedure for storing abrasive wheels?
- Dry, temperature-controlled storage racks or pegboards; wheels must not be stacked flat, must be protected from impact, and must be used in date order (FIFO) (Correct answer)
- Wheels can be stored in any dry location including on the workshop floor
- Stacking wheels on top of each other is acceptable if they are wrapped
- Temperature is irrelevant — only moisture affects wheel integrity
Correct answer: Dry, temperature-controlled storage racks or pegboards; wheels must not be stacked flat, must be protected from impact, and must be used in date order (FIFO)
Abrasive wheels must be stored in a dry, temperature-controlled environment on proper racks or pegboards designed to prevent rolling or impact. Flat stacking causes stress concentrations. First-in, first-out usage prevents old wheels being used beyond their usable life. Extremes of temperature and moisture can affect resinoid bonds.
Abrasive Wheels Training Certificate Safe Mounting & Dressing Procedures 2
What is 'wheel dressing' and what tool is used for it?