Abrasive Wheels Training Certificate Abrasive Wheel Types & Grades 1

Question 1

Which BS EN standard specifies the safety requirements for abrasive wheels used with angle grinders?

Accepted Answer

BS EN 13743 and BS EN ISO 603

Answer

BS EN 13743 and BS EN ISO 603 cover the dimensions, tolerances, and safety marking for resinoid and vitrified grinding wheels for portable grinding machines. These standards define maximum operating speed, dimensions, and marking requirements.

Question 2

What does the 'grade' of an abrasive wheel refer to?

Accepted Answer

The hardness of the bond holding the abrasive grains together

Answer

The grade (or hardness) of an abrasive wheel describes how strongly the bond holds the abrasive grains. A hard-grade wheel retains its grains longer; a soft-grade wheel releases worn grains quickly, exposing fresh sharp ones. Selecting the correct grade for the workpiece material is critical to safe performance.

Question 3

What is the purpose of the 'structure' designation of an abrasive wheel?

Accepted Answer

To indicate the spacing (porosity) between abrasive grains — open structure for soft materials, dense structure for hard materials

Answer

Structure refers to the volumetric distribution of abrasive grains, bond, and voids (pores). An open structure (widely spaced grains) provides chip clearance for soft, sticky materials. A dense structure suits hard materials requiring fine surface finish. Incorrect structure can cause glazing or wheel loading.

Question 4

Which bonding material is most commonly used in abrasive wheels for general grinding?

Accepted Answer

Vitrified bond (ceramic)

Answer

Vitrified bond wheels are the most common for general precision grinding. The vitrified (ceramic) bond is rigid, porous, and temperature-resistant. Resinoid (resin) bonds are used where strength and some flexibility are needed, such as cut-off wheels and angle grinder discs.

Question 5

What is the purpose of the abrasive grain type designation on a wheel specification?

Accepted Answer

To identify the abrasive material (e.g., aluminium oxide for steel, silicon carbide for non-ferrous) for matching to the workpiece

Answer

Aluminium oxide (Al2O3) abrasive is suited to ferrous metals (steel, iron). Silicon carbide (SiC) is used for non-ferrous metals (aluminium, brass), stone, and ceramics. Using the wrong abrasive for the material results in inefficient cutting, overheating, or wheel damage.

Abrasive Wheels Practice Test

Abrasive Wheels Practice Test

Abrasive Wheels Training Certificate Abrasive Wheel Types & Grades 1