Choosing the Best Abrasive Machining Technique for Portable Grinding Applications

Read more: “What Are the Right Abrasives for Your Metal Removal and Finishing Work?”

High Abrasive Prices vs. Low Abrasive Prices: What’s Best for You?

And what about manufacturers that aren’t doing high-volume work? There are countless job shops and fabricators that make 10 of this, or 100 of that, and feel it makes more sense to toss partially consumed discs into the trash rather than manage them. In this situation, are higher-priced premium abrasives still the answer?

Yes, says 3M Application Engineer William Maher.

“Let’s say you’re using a depressed center grinding disc and it wears to the point that it can no longer reach a fillet weld,” he says. “Instead of throwing it out, you might move the disc over to a chamfering operation, or another type of edge preparation where diameter is less of a factor. Or maybe you use another type of abrasive entirely—a belt product, perhaps, on a portable file tool. Figuring out which solution is most effective is all about operator training and exploring the wide array of abrasive shapes and media that are currently available.”

Operator training is important for other reasons. SBD’s Sellers notes that grinding operators tend to use a finer grit disc than they should, opting for an 80-grit disc (which they consider coarse) when they should be using a 24- or 40-grit disc instead. And those who do move into ceramic abrasives find that they cut more freely than others, an advantage that might require operators to adjust their grinding style.

They probably won’t complain, however, as freer-cutting discs mean less fatigue and a happier workforce—two outcomes that help explain the industry’s push toward high-performance abrasives.

Sellers also says a higher level of inventory control is advisable when using premium abrasives, just as it is with any shop’s more expensive or production-critical consumable items.

In all but field applications, he recommends using an automated vending machine approach when dispensing tools to workers, with the costs for those tools automatically allocated to the department or job. This provides greater accountability and cost tracking.

As he and others point out, the price of greater productivity goes beyond consumable cost—it could also mean investment in new grinding equipment.

Just as abrasives have improved over the years, so too have portable grinders, with lightweight but powerful devices widely available. This means shops can use larger discs without increasing the level of operator fatigue, further improving throughput. Adding a ceramic abrasive to the mix, which tends to reduce grinding forces and allow even small portable grinders to be effective, creates a best of both worlds solution.

How to Find the Best Flap Disc

There’s also strong agreement on the styles of coated abrasive discs that are most effective. Patrick Carroll, product manager at Norton Saint-Gobain, notes that flap discs are now the preferred approach for many applications thanks to their wide-ranging capabilities.

“One of the advantages of a flap disc is that it can grind and finish equally well,” Carroll says. “There are some products that just grind, and others that just finish, whereas flap discs can cover heavy stock removal all the way to blending and finishing in one step.”

Explore the Grinders & Abrasives Guide on MSCdirect.com to select the best tool for your grinding operation

Alicia Castagna, Norton Saint-Gobain product manager for thin-wheel abrasives, explains that there’s more to this story than the abrasive alone—there’s also density to consider, along with the disc’s backing.

“We and others offer standard and regular densities, which refers to the number of flaps you put on a disc,” she says. “As a rule, higher density provides up to 40 percent greater life in addition to ceramic’s fast cut rates. There are also different options in terms of fiberglass versus plastic backings, and conical versus flat disc shapes. Each provides different ergonomics and material removal capabilities, and like the choice of abrasive, should be evaluated based on the specific application and the shop’s budget.”

These are just a few small slices of the abrasive pie, of course. These companies (and numerous others) all have a broad assortment of abrasive solutions, including various blends of ceramic and more traditional media, different pricing tiers, and many other variables that make it difficult to offer generalized recommendations.

That said, ceramic-based abrasives, as well as those made of zirconia, tend to provide higher cut rates and greater durability, both of which lead to a lower cost per part overall. When combined with newer grinding equipment, shops can greatly improve their metal finishing and weld prep capabilities while making the job easier to boot. Maybe it’s time for an abrasive upgrade?