Grinding Wheel

Straight grinding wheels are usually used in bench grinders.

Cylinder grinding wheels are used in horizontal or vertical spindle grinders to make flat surfaces.

Tapered grinding wheels are wider in the centre with a surface that tapers outwards. These wheels are used to grind gear teeth or threads.

Straight cup grinding wheels are fitted to cutter machines and used to sharpen tools or to make flat surfaces.

Dish grinding wheels are thin with a flat centre that is raised outwards on the edge. These wheels are commonly used to cut openings such as slots.

Saucer grinding wheels have a straight edge section and are used for twist mills and grinding cutters. 

It has always been recommendation that resinoid bonded grinding wheels be used up within 2 years from the date of manufacture. This recommendation assumes that resinoid bonded grinding wheels have been stored under ideal storage conditions. It may be true under ideal storage conditions resinoid bonded grinding wheels can survive without any degradation in strength for well over two years. It is always wise to suspect any wheels over two years old and have them reinspected or re-speed tested to determine if there has been any degradation in strength. If the wheels are stored under less than ideal conditions, they may have a much shorter shelf life depending upon the severity of storage conditions.

These same comments also apply to rubber and shellac bonded grinding wheels. As for vitrified grinding wheels, the shelf life is less influence by humidity and adverse storage conditions as compared to resinoid, rubber or shellac, but even vitrified grinding wheels do not have an infinite shelf life.

The best procedure and the best rule of thumb is to have any wheel that is two years old or older re-speed tested and reinspected to ensure it is fit for use.

Keep in mind that this procedure is good to verify the reliability of a product but must not be performed until you are ready to consume the wheel. If wheels are sent back after the two year time frame for reinspection and retesting and then put back on the shelf, there is no telling how long they will be fit for use after that last inspection.  

The abrasive grains provide the essential functionality of a grinding wheel because they remove material from the workpiece. A few commonly used grinding wheel abrasives are ceramic alumina, zirconia alumina, aluminum oxide, white aluminum oxide, aluminum oxide and silicon carbide. Grains can be blended together to achieve different performance characteristics as well.

● Ceramic alumina: These grains offer the benefit of self-sharpening and micro-fracturing crystals. They are relatively cool when in use, and they provide the longest operating life under moderate to high pressure. They grind at lower temperatures and generate less friction — one main benefit of these qualities is that they minimize heat discoloration on the workpiece. Ceramic alumina is ideal for hard-to-grind metals such as armored steel, titanium, hard nickel alloys, tool steel and stainless steel.

● Zirconia alumina: Zirconia alumina grains provide a fast cut and a long life on metal workpieces. They are self-sharpening and deliver rapid, consistent grinding, especially on metals like steel and stainless steel. They also hold up well under high pressures and extreme temperatures.

● Zirconia alumina blended with ceramic alumina: If you like the performance of a zirconia alumina grinding wheel but are looking for an extra boost a blend with ceramic alumina will deliver faster cutting with less effort.

● White aluminum oxide: White aluminum oxide grinding wheels offer a relatively fast cut-rate and an extensive lifespan. They are ideal for grinding stainless steel and harder-grade steel.

● Aluminum oxide: An aluminum oxide grain is ideal for steel, iron and other metals. Although it is hard and durable and provides a sharp, fast initial cut, the grain dulls over time and lacks the cut-rate and potential longevity of some other grains.

● Silicon carbide: Silicon carbide is an extremely hard grain that is very sharp and fast cutting but friable, not as tough as other grains.

● Silicon carbide/aluminum oxide blend: A wheel made from a blend of silicon carbide and aluminum oxide provides ideal grinding for aluminum and other soft alloys. These grains offer extended life spans and fast, consistent cut rates on aluminum and other soft metals. 

Abrasive is the material from which the wheel is made. This is what does the work. Most common abrasives include, Aluminum Oxide, Silicon-Carbide, Zirconia Aluminum Oxide, Cubic Boron Nitride (CBN) and Synthetic Diamond.

Next is Grit. This is the size of the abrasive grain in the wheel. As you probably know, the lower the number, the coarser the grit. Coarse grits are used for soft, pliable, stringy materials when you want fast material removal, have a large contact area and high pressure. Finer grits are used to produce smooth finishes and when you're grinding hard, brittle materials and have a small contact area.

Coarse grits are 8, 10, 12, 14, 16, 20 and 24
Normal grits are 30, 36, 46, 54, 60 and 70
Fine grits are 80, 90, 100, 120, 150, 180 and 220
Very Fine grits are 240, 280 and up

Grade refers to the strength of the bond (we'll get to bond in a bit) that holds the abrasive grains together. This can range from very soft to very hard and is represented A to Z in grinding wheel specs.

Softer grade wheels cut faster with less chatter. They require lower amps or power to drive them, have shorter wheel life and produce a worse finish. Harder grades cut slower with more chatter. The produce a better finish and have a longer life, but require more power/amps to operate.

Structure denotes the spacing of the abrasive grains in the wheel. The lower the structure number, the denser the wheel. Structure numbers range from 0 to 14. 

These high speed abrasive discs can be extremely dangerous if used incorrectly. Below are some basic tips for grinder wheel safety that should always be observed, even if you're just doing quick touch-up work.

● Always wear proper PPE

● Always inspect your grinding wheels before use for any damages, such as defects, cracks, or chipping

● Always match the diameter of the grinding wheels with the appropriate angle grinder

● Never remove or modify the angle grinder guard

● Never use an angle grinder with a higher RPM rating than the wheel

● Always allow the grinder to warm up, coming up to full speed before each use

● Always allow the grinder to come to a complete stop after use

● Always use two hands on your angle grinder

● Do not wear baggy clothing while operating an angle grinder 

Ningbo Dahua Grinding Wheel Co.,Ltd. Is a well known Chinese company specialized in Researching and producing resin abrasive products. It was found in 1996, mainly produce fiber reinforced resin cutting and grinding wheel, rail cutting and grinding wheel, ordinary resin grinding wheel, fiber glass etc. The factory has Industrial Production License and Independent Exporting License. In the past 20 years, it sales to more than 70 countries in the world and the quality of products is universally recognized.
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The company will go on struggle as always, renew and improve the quality of products constantly, maintain good services and competitive prices. Warmly welcome you to negotiate cooperation and create better business value.