Abrasive Wheels Training Certificate Inspection and Storage 2

Question 1

Why must abrasive wheels be protected from frost during storage?

Accepted Answer

Water absorbed into the wheel can freeze and expand, causing internal cracks

Answer

Moisture that has been absorbed into an abrasive wheel (particularly resinoid-bonded wheels) can freeze and expand during cold conditions. This expansion creates internal micro-cracks that weaken the wheel structure and can lead to catastrophic failure during operation.

Question 2

What should an operator do if they discover a crack in an abrasive wheel during a pre-use inspection?

Accepted Answer

Immediately remove the wheel from service and destroy it to prevent reuse, then report the finding

Answer

A cracked abrasive wheel must never be used. It should be immediately removed from the machine and destroyed (broken up) to ensure it cannot be inadvertently refitted. The finding should be reported to the supervisor. A cracked wheel can disintegrate at operating speed with lethal consequences.

Question 3

What is the purpose of 'dressing' an abrasive wheel?

Accepted Answer

To restore the cutting face by removing glazed or loaded material and truing the wheel surface

Answer

Dressing an abrasive wheel removes glazed, loaded (clogged), or unevenly worn material from the cutting surface and restores its true round shape. This is done using a dressing tool (typically a diamond or star-type dresser). Regular dressing improves cutting efficiency and reduces vibration.

Question 4

How should large vitrified abrasive wheels be stored?

Accepted Answer

Stored on edge in suitable racks, supported to prevent rolling

Answer

Large vitrified wheels should be stored on edge in suitable racks with supports to prevent them from rolling. Stacking flat can cause the bottom wheels to crack under the weight of those above. Small wheels can be stored flat with separators between them.

Question 5

What is 'glazing' of an abrasive wheel and why is it a problem?

Accepted Answer

The abrasive grains become worn flat and smooth, reducing cutting ability and increasing heat and friction

Answer

Glazing occurs when the abrasive grains become worn flat and smooth rather than fracturing to expose fresh cutting edges. This reduces cutting efficiency, increases friction and heat generation, and can cause workpiece burning. A glazed wheel needs to be dressed to restore its cutting ability.

Abrasive Wheels Practice Test

Abrasive Wheels Practice Test

Abrasive Wheels Training Certificate Inspection and Storage 2