Abrasive Selection – How do you select your abrasives?

This one is colourful! One welder likes this brand and another swears by that brand!? Where are these things made anyway, I hear Germany makes good cars and abrasives… I wonder if this company is manufacturing abrasives or just marketing them? My buddy says this is the best grinding wheel so it must be true, and so on… I hate to break it to you but this is how most decision makers select which abrasives to use in their shop.

Perhaps the answer is, what questions should I ask? How often does a salesman come into your shop and drop off a box of abrasives and say “try these and let me know”, then you respond with “these ones suck” or “they glazed up or disintegrated”. Let’s look at what is actually happening here. This salesperson may have good intentions (or not) but they are wasting your time and theirs. Without understanding the specific application there is a very small chance that the abrasive will match your specific applications.

There are lots of factors to consider when selecting the correct abrasive, so let’s get started.

  1. Soft bond vs hard bond grinding. Edge and bevel grinding requires a harder bond while stock removal requires a softer bond. If you use a hard bond where a soft bond is required, such as removing or ‘flattening’ welds, the wheel may glaze up or simply not be effective. Alternatively, if you’re running a soft bond to edge and bevel grind all day, your wheel will disappear, very quickly! The bond hardness scale is based on a rating system and it uses the alphabet. A softer bond typically starts with an “R” while a hard bond is a “T” bond. Every reputable manufacturer should be indicating this information on their wheel. Being aware of this scale and simply matching the right bond with your application can save your shop thousands of dollars a year, as well as save time by not switching abrasives unnecessarily because your welders think you need a ‘better one’.
  2. Designed for specific purpose. There seems to be a trend in the industry – 2 in 1, All in one, Combination disc… This is just marketing and unless your projects are limited too cutting metal junk in your garage you should be using the right disc for the job! For example, while a stainless wheel will grind on carbon steel, it is certainly not going to remove material efficiently… I wonder why. Just like a broom and a shovel serve two different purposes, so do different abrasives bonds, resins and fibers! Stop thinking you can buy one abrasive for all your needs then tell your employees to get back to work when they complain that the disc isn’t performing.
  3. Ask the Pros… Just like when you buy a house, you speak to a realtor. When you select an abrasive ask to speak with the factory rep. If they aren’t knowledgeable don’t waste your time, move on. Learn how to say no, don’t drag it out, your time is valuable.
  4. Cost vs performance. A cheap grinding wheel is expensive, and the expensive wheel is actually the cheaper way to go! Allow me to explain. When you buy a cheap grinding disc you are doing so to save money but what you must realize is you are buying a cheap wheel because you’re too lazy to put the work into educating/disciplining your work force and/or finding the correct wheel for the application. If this is your mindset then keep buying cheap wheels! Know you are overpaying because you will never get the life and performance out of the wheel and if you go too cheap one day you are putting your employees at risk of injury or death by exploding wheel. When you combine a premium grinding wheel on the correct application, with an experienced operator… magic happens. The cost of the “expensive disc” actually goes down because the wheel is removing material or stock as designed. The operator isn’t exhausted as quickly and you achieve the proper life cycle out of the wheel! This allows for fewer disc changes (and visits to BS with cute tool crib girl), improved jobsite moral and consistent fabrication. Time is money!
  5. Buy from one source. When you find the right abrasive, convert all your business to one manufacturer. The advantage to this strategy is a lower cost by bundling your consumables and buying in volume. You cannot do this when you buy from 12 different abrasive manufacturers because your welders are running your shop and can’t decide what colour of disc they like today.
  6. Run proper tests. If you don’t understand the test, you are being taken advantage of, period. Instead of assuming your welders know everything about the abrasive you throw at them to test in one afternoon consider putting different manufacturer reps against one another for a demo day. Kill, two, three, four, birds with one stone and have them all test against one another. Think about it, instead of running 4 tests on 4 different days, burning up all that time for a mixed result because too many variables changed from test to test, do it at one time! There are two main types of abrasive testing that takes place in the field. G-ratio and the performance/time test. G-ratio is done by weighing the metal and abrasive, before and after and calculating the difference. Speed can also be accounted for depending on the application. This is a good test but requires a disciplined group and a controlled environment. A more practical test for say cutting or grinding is to have the same welder run the grinder on two identical applications. Run an in-line amp meter and a stopwatch, simultaneously. The amp meter serves two purposes. It keeps the test fair in case the welder has a bias for one brand over the other and allows the decision maker to document and consider the amp range while grinding. Keep in mind running grinders with less amps can mean, less grinder repairs, less exhaustion, more productivity, longer life and fewer disc changes. It can also speak volumes as to the quality of the abrasive. If you welders need to break their backs pushing on a grinder all day, you have the wrong product for your application. Let the wheel do the work!
  7. Who is calling the shots? Whether you are the owner, general foreman or project manager, you are the decision maker. Don’t let your employees or subcontractors call the shots or make excuses about one brand over another. Take ownership and make a business decision. A good welder will make it work, if you have done your homework, matching the product with the application, your welders will be happy and your company is on track for a project finished on time and under budget for once.

Jamieson Byrt – Cutting Edge Industrial Sales – Edmonton, AB