Abrasive Wheels Training Certificate Abrasive Wheel Types & Grades 2

Question 1

What type of abrasive wheel is a 'cut-off wheel' (parting wheel) designed for?

Accepted Answer

Cutting through materials in a straight line; it has a thin profile and should not be used for side grinding

Answer

Cut-off (parting) wheels are thin-profile wheels designed solely for cutting through material. Their thin cross-section makes them structurally unsuitable for lateral forces. Using a cut-off wheel for side grinding will cause flexing, possible cracking, and potentially catastrophic burst. They should only be used for straight cutting.

Question 2

What is a 'flap disc' and how does it differ from a conventional grinding wheel?

Accepted Answer

A disc made of overlapping abrasive flaps; it is more flexible than a rigid grinding wheel and provides a better surface finish

Answer

Flap discs consist of overlapping strips (flaps) of abrasive cloth or paper bonded to a backing plate. They are more flexible than rigid grinding wheels, conform better to curved surfaces, and produce a finer finish. They are used for blending, finishing, and light stock removal on angle grinders.

Question 3

Diamond cutting wheels are different from conventional abrasive wheels in which key respect?

Accepted Answer

Diamond grains are embedded in the wheel bond and do not break down during cutting; the wheel cuts by abrasion with extremely hard industrial diamond

Answer

Industrial diamond wheels use synthetic diamond particles, the hardest known material, bonded to a steel or aluminium substrate. Unlike conventional abrasive wheels where grains break down, diamond grains endure. Diamond wheels are used to cut extremely hard materials: concrete, masonry, glass, and ceramics.

Question 4

What does the 'specification code' printed on an abrasive wheel tell the user?

Accepted Answer

The abrasive type, grain size, grade (hardness), structure, and bond type in a standardised sequence

Answer

The standard specification code (e.g., A 36 L 5 V) reads: A = aluminium oxide abrasive, 36 = grain size, L = grade/hardness, 5 = structure, V = vitrified bond. This sequence (ANSI/ISO standard) allows the user to identify exactly what the wheel is made of and select the correct wheel for the application.

Question 5

Why must the bore size of an abrasive wheel match the spindle exactly?

Accepted Answer

A loose bore allows the wheel to run off-centre, creating imbalance, vibration, and the risk of the wheel cracking or bursting

Answer

The bore must be a proper fit on the spindle — neither loose nor requiring force to fit. A loose bore allows eccentric rotation, creating dynamic imbalance and vibration that can propagate cracks and lead to wheel burst. Reducing bushes can be used to adapt bore size but must be the correct type for the wheel.

Abrasive Wheels Practice Test

Abrasive Wheels Practice Test

Abrasive Wheels Training Certificate Abrasive Wheel Types & Grades 2