Abrasive Wheel Types and Selection Flashcards
6 cards from real Abrasive Wheels Training Certificate practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Abrasive Wheel Types and Selection flashcards as text
Which grade of abrasive wheel should be selected for grinding hardened steel?
Answer: A soft grade wheel (A-H)
A soft grade wheel (A-H) should be used for grinding hard materials. Soft wheels release worn grains more easily, exposing fresh cutting edges. Hard wheels are used for soft materials. This is known as the 'reverse rule'.
What is a Type 27 abrasive wheel commonly known as in the workplace?
Answer: A depressed centre grinding disc
Type 27 wheels are depressed centre grinding discs, commonly used on angle grinders. The depressed centre allows the wheel to grind flush against the workpiece without the spindle nut interfering.
What is the main difference between an organic bond and a vitrified bond in abrasive wheels?
Answer: Organic bonds (resinoid/rubber) are more flexible and shock-resistant than vitrified bonds
Organic bonds (resinoid and rubber) are more flexible and shock-resistant, making them suitable for portable and hand-held grinding. Vitrified (ceramic) bonds are rigid and brittle but offer excellent heat resistance and are used for precision grinding.
When selecting an abrasive wheel for use on an angle grinder, which specification must always match?
Answer: The bore size must match the grinder spindle diameter
The bore size (centre hole) of the wheel must exactly match the spindle diameter of the grinder. An incorrect bore size will cause the wheel to be off-centre, leading to dangerous vibration and potential wheel failure.
What does an 'open' structure number (7-14) in an abrasive wheel marking indicate?
Answer: The wheel has fewer abrasive grains with more spacing between them
Structure numbers range from 0 (dense/closed) to 14 (open). Higher numbers indicate wider spacing between grains, which provides better chip clearance and is suited for softer, gummier materials that would otherwise clog the wheel.
Which type of abrasive wheel is specifically designed for use in cutting-off operations and is typically very thin?
Answer: Type 1 (flat/straight) cutting disc
Type 1 flat cutting discs are specifically designed for cut-off operations. They are manufactured very thin (typically 1-3mm) to minimise material waste and reduce heat generation during cutting. They must never be used for side grinding.