What to Consider When Shopping for a Grinding Wheel
In the world of metalworking, there are several products that can be used for a whole range of grinding applications. Getting the wrong one can be expensive, both in cost and time, so make sure you’ve looked into every detail before you pay for anything.
When in the market for a grinding wheel in particular, the material to be ground is the first consideration you should make. This will clue you in on the best type of abrasive for the wheel.
For steels and steel alloys, for instance, aluminum oxide or zirconia alumina works great. Non-ferrous metals and cast iron, along with non-metals, are best ground using a silicon carbide abrasive.
Hard and brittle materials often need a wheel that has a fine grit size and a softer grade. Hard materials contradict the force of abrasive grains, dulling them pretty quickly.
Thus, with a combination of a finer grit and a softer grade, abrasive grains can detach as they dull, exposing new, sharp cutting points. On the other hand, if you plan to grind soft, ductile and easily penetrable materials, you can use a coarse-grit and hard-grade wheel.
Another thing to be considered when shopping for a grinding wheel is how much stock must be removed. Since coarser grits can penetrate more and make heavier cuts, stock removal becomes faster too. But if the material is too tough, you can use a slightly finer grit wheel, which has more cutting points, for faster cuts.
Faster cuts can be achieved using a wheel with vitrified bonds. For smaller stock removal or if finish requirements are higher, choose resin, shellac or rubber bonds.
Another thing you should consider when choosing a wheel bond is wheel’s speed while in operation. The maximum speed for vitrified wheels is 6,500 surface feet per minute; any faster and the bond may break. Organic bond wheels are often the choice between 6,500 and 9,500 surface feet per minute.
If a higher speed is needed, wheels can be custom-made for the specific purpose. Whatever the case, always check the safe operating speed – usually in rpm or sfm – indicated on the wheel or its blotter, and make it a point never to go beyond it.
Before buying a grinding wheel, also check the grinding area of contact between it and the material to be ground. A bigger area will necessitate a softer grade and a coarser grit, if only to ensure free gliding cutting action. Now look into the severity – the pressure that makes the wheel and the workpiece stick to each other – of the grinding action. Keep in mind that the ability of abrasives to endure grinding conditions varies, depending on how they are made.
The last but no way the least consideration to make is the grinding wheel’s horsepower. In most cases, higher grade wheels are used with machines with higher horsepower. If wheel diameter is greater than horsepower, it is best to use a softer-grade wheel. Otherwise, use a higher-grade wheel.