During the grinding process, the abrasive grains in the grinding wheel ensure that the material of the workpiece is removed. The choice of grinding wheel grit (grain size and hardness) depends on the surface of the material to be processed and the application. The coarser the grit size, the more the material to be processed is removed. A grinding wheel with a coarse grit is therefore better suited for rough grinding. A finer grit is particularly suitable if a high surface quality of the material to be worked on is to be achieved, i.e. for fine grinding and polishing work.
All abrasives are classified according to their grit size into the categories “coarse”, “medium”, “fine” or “very fine”. The grit sizes range from P12 (coarse) to P5000 (very fine) for flexible abrasive products (grinding paper, abrasive belts, flap discs, coated abrasives) and F4 (coarse) to F2000 (very fine) for non-flexible abrasive products (grinding wheels, cut-off wheels). The smaller the number, the coarser the grain.
The hardness of a grinding wheel is the resistance that the bond offers to the grinding wheel when the abrasive grain breaks out. The harder the material to be processed, the softer the bond should be. However, a very soft bond also leads to faster wear.
The degree of hardness is indicated by A (extremely soft) to Z (extremely hard).
For processing wood, a distinction is made between flexible hand abrasives for curves and edges and grinding tools for machine hand grinding and for surface processing. Grinding papers or cloths for hand grinding, grinding discs for orbital sanders or delta sanders, grinding belts for belt grinders or also non-woven products or flap discs are used here. When grinding wood, it is important to always work in the direction of the grain.
For processing metals, e.g. for removing rust and welding seams or for removing lacquer, rein-forced grinding wheels are suitable, but also flexible abrasives such as fibre discs, flap discs or abrasive belts. Cut-off wheels are used for cutting metal.
Always wear personal protective equipment when grinding: eye, ear, hand and respiratory pro-tection.
In the field of hand-held grinding machines, there are a whole range of different machines such as angle grinders, random orbital, orbital or delta grinders, straight grinders or belt grinders.
The angle grinder is suitable for a wide variety of cutting, grinding and polishing work. Materials such as wood, metal, stone or concrete can be processed with it. Cut-off and grinding discs or fibre and flap discs are used. Random orbital, oscillating or delta grinders are suitable for grind-ing and polishing flat surfaces, preferably wood and metal. Round or square grinding papers are used, which are fixed by means of Velcro or clamps. Delta grinders with special triangular grind-ing attachments allow grinding in hard-to-reach angles and corners. Straight grinders are suitable for grinding and deburring different materials and for buffing welding seams. Shaft tools such as mounted points are used here, but also flap wheels or grinding wheels and grinding discs for wheel grinders. Belt grinders are suitable for high removal rates when grinding large surfaces.
Always wear personal protective equipment when grinding: eye, ear, hand and respiratory protection.
When it comes to safety, we recommend using grinding wheels that are marked with the oSa label. oSa labelled grinding wheels stand for the highest possible level of safety.
Always wear personal protective equipment when grinding: eye, ear, hand and respiratory pro-tection.
The following rules must be observed when storing grinding wheels:
• For storage after use, the product should be dried and residue removed from the product surface.
• Storage should be in the original packaging on a flat surface.
• Storage should be dry and frost-free.
• Avoid large temperature fluctuations.
Resin-bonded grinding wheels in particular must always be stored in a dry place, as moisture can reduce the strength of the grinding wheel.
A grinding wheel with coarse grit is better suited for rough grinding. A finer grit is particularly suitable if a high surface quality of the material to be processed is to be achieved, i.e. for fine grinding and polishing work.
Always wear personal protective equipment when grinding: eye, ear, hand and respiratory pro-tection.
GS marking: The GS mark (“Tested Safety”) is a state-regulated but voluntary test mark in Germa-ny in the Product Safety Act (ProdSG), which is only used for ready-to-use products, i.e. not for grinding wheels. Grinding wheels are usually used with a machine and therefore cannot be marked with GS.
CE marking: Abrasive products as accessory tools according to the Machinery Directive do not fall under the requirements of CE marking and therefore cannot be marked with CE.
ISO marking: ISO certification is intended for companies, institutions and authorities, but not for the products that are manufactured. Therefore, abrasive products cannot be marked with ISO.
The expiry date is mandatory for resin bonded grinding tools (thin wheels, cut-off and deburring grinding wheels) for hand-held machines (e.g. angle grinders) and is anchored in the European safety standard EN 12413. It must not exceed more than 3 years after the date of manufacture and is usually expressed as month and year on the metal ring of the grinding wheel. The applica-tion of this standard is voluntary for the manufacturer. oSa members undertake to apply the EN safety standards for abrasive products. In Italy, an expiry date for resin bonded grinding wheels is required by law.