Compact loaders have become a valued tool for the modern tree care crew, creating easier access through relatively tight spaces and saving significantly on labor and injuries. More and more, crews arrive at job sites with a stump-grinder attachment for a compact loader, making backyard stump work more accessible and the tool more versatile.
“The performance is going to be somewhat limited, because you’re dealing with the hydraulic output instead of a direct-drive engine,” says Bill Schafer, product manager for Loftness, a 19-year TCIA corporate member company based in Hector, Minnesota, which is in the process of adding the tool to its offerings. “The beauty of it is that you’re utilizing an engine that you’re already maintaining in the compact loader. Skid steers are known for that. In the last few years, we’ve enjoyed a huge benefit in the increased power they’re giving us on hydraulics to do more and more things.”
Unlike a trailer-mounted stump grinder, loader-mounted units have great maneuverability, comparable to or even greater than the self-drive stump grinder machines, according to Schafer. They’re also lighter than the older trailer-mounted units, which means they have less negative impact on the work site, he says.
“They skinny-down (meaning the tracks contract) to fit through a 36-inch gate,” says Logan Yuncker, inside sales coordinator for Morbark, LLC – a 42-year TCIA corporate member company based in Winn, Michigan – of Morbark’s Boxer loaders. Morbark has been producing compact loaders since 2012 and stump grinders since 2017, following acquisitions of other companies. They sell Bradco and Erskine stumper attachments for their loaders.
Morbark’s loaders have working capacities that range from 375 pounds all the way up to 700 pounds. “That’s what their operating capacities are rated at, which is 35% of the tipping load. There are four different models, one gas and three diesel,” says Yuncker.
Stump-grinder attachments come with many of the same safety features that their larger, direct-drive counterparts do – chip-protection shields and more, he says.
“We offer three different models, two of which are fixed and have different hydraulic-flow requirements,” says Yuncker. “The other model is an articulating model. This model is great to have and doesn’t require you to move the machine side to side as you are grinding a stump. It also will work on every model Morbark offers. They all come with interchangeable teeth for any manufacturer, universal mount and hydraulic hoses.”
Toro’s stump-grinder attachment has a 17-inch cutter wheel with 12 cutting teeth, a wheel speed of 2,000 revolutions per minute (rpm) and a tooth-tip speed of 148 feet per second, according to Kyle Cartwright, marketing manager for Toro. It also offers a 36-inch-above-grade maximum cutting height and a 16.5-inch-below-grade maximum cutting depth, to ensure that all stump material can be sufficiently removed.
It attaches to any compact utility loader in the company’s Dingo line by turning two locking pins and connecting two hydraulic lines. The hydraulic system produces 12 gallons per minute (GPM) of flow at 3,000 pounds per square inch (psi) of hydraulic power.
“Traditional, larger grinders are unable to reach into tight or confined spaces,” says Cartwright. “Because the Dingo loaders with the stump-grinder attachment feature a compact design, users can maneuver into confined areas, saving valuable time.”
Smaller machines offer their own efficiencies, but users should be aware of the realities, and limitations, of these smaller units.
Dynamic and small
Joe Leonardi is the third-generation president of Leonardi Manufacturing, a 29-year TCIA corporate member company based in Weedsport, New York. The company makes the teeth and wheels for stump grinders, and also developed what Leonardi describes as the “time- and effort-saving” Chipshoot, which collects chips in a manner similar to how a lawn-mower bag collects clippings for controlled disposal. Leonardi notes that most modern machines can grind a large stump in 15 to 20 minutes, “and the cleanup is an hour-and-a-half or two hours.”
Definitions of “compact” can vary, Leonardi notes, but there is definitely a trend in the industry toward smaller, more versatile loaders. “A lot of these smaller, standup machines will go through a 36-inch gate,” Leonardi says, but adds that most direct-drive stump grinders also will go through a 36-inch gate.
While stump-grinder attachments offer versatility and options, grinding a stump isn’t necessarily a one-size-fits-all chore. Even a tool that will get a job done isn’t always the best tool for the job.
“It’s just like anything,” Leonardi says. “Nothing is good for all scenarios. You just have to be patient on a big stump. When you start getting a two-foot-diameter stump, or larger, you’re going to start taking quite a bit of time to get it done.
“We make wheels for some handlebar machines,” which require the user to supply force, Leonardi continues. “We’ve designed a wheel specifically targeted for lower-horsepower machines, as well as a different wheel designed for larger-horsepower units, and they cover from 6 to 600 horsepower. In the 6-horsepower range, they’re a handlebar machine. When I first heard about it, I kind of dismissed it, but it works great for really small stumps. And I’ve seen operators take on some good-sized stumps, in that 2- to 3-foot range. It just takes them a long time.”
The stump grinders used on compact loaders are built with most of the same safety guards larger units have, but Leonardi notes that the size and quality of shields “range quite a bit, depending on the manufacturer.” Operators need to be aware of the differences and know how much flow and horsepower they are using.
“One of the big things with any (grinders) of the attachment style, where it’s a compact or larger loader, is that they allow you to raise the grinder high in the air,” Leonardi says. “When you raise it up in the air like that, your guarding is very much compromised, and you want to be really careful. If you’re in the woods someplace, who cares. But if you’re in a residential area, you’ve got to be careful.”
Along with the size of the wheel, another factor that distinguishes this type of stump grinder from others, and each other, is the amount of hydraulic flow available.
“At the end of the day, it’s about horsepower,” Leonardi says. “There’s no substitute for horsepower. And in these types of applications, it comes down to flow. How much hydraulic flow and pressure do you have in small machines, if they don’t have a high-flow option on them?
“You’ve got to think about how much actual horsepower you are getting to that head,” Leonardi says. “Then, of course, is the cutting tooth well sized for that horsepower? For instance, we make a different tooth, a different wheel combination, for the smaller machines, but we specifically designed it for the small machines.”
Typically, a stump grinder used on a compact loader is 25 to 30 horsepower, according to Leonardi, who adds that small-horsepower machines are very sensitive to having a sharp edge on the tooth. “So, for a smaller machine with our Blueshark system, you get the ability to index the tooth of the cutting wheel to get more cutting edges from it. That is sometimes necessary with the smaller, and smaller-horsepower, machines, because the cutting edges can wear down.”
While the smaller stump grinders can get the job done, they’re not always the best tool for the job.
“Certainly, if the real estate or geographic area is large enough and roomy enough, you’d be more productive with something bigger, if the job warrants that,” Loftness’s Schafer says. “Compact equipment by nature is targeted toward more compact areas or more limited spaces.”
“They’re all going to relate to horsepower that is provided. It would just be a matter of recognizing the capabilities. A hydraulic-driven unit is going to be limited to the hydraulic horsepower developed by its auxiliary setup. It’s an easy formula. On any given combination of hydraulic auxiliary output, you take the GPM times the psi and you divide by 1,714.
“That’s the whole formula,” Schafer continues. “So if the reader was to do that, and they are comparing to a 50-horsepower, self-contained, engine-driven unit, and its hydraulics has 20 gallons at 3,000 psi, if we do the math, it’s probably only going to have 35 (hydraulic horsepower). It’s in direct proportion to the horsepower going into it. To match the 50-horsepower, engine-driven unit, you would need approximately 30 gallons at 3,000 psi, which calculates to 52.5 horsepower.”
A growing area
Loftness is so new to the market for stump-grinder attachments for compact loaders that models hadn’t even appeared yet on the company website when the interview for this article was conducted.
“It’s a strong market, and we see potential there,” Schafer says. “You’re in the right direction with the idea that using compact equipment for smaller jobs is a natural. And the fact that the attachment becomes self-propelled simply by mounting it directly on the loader arms gives you, in essence, a self-propelled stump grinder.
“Something worthy to note is that the operator is truly contained in a (loader’s) cab, instead of being out beside this unit,” Schafer says, pointing out that that is a significant safety factor.
Leonardi’s advice for buyers is to get some hands-on experience with whatever model they’re interested in.
“If you are considering one, try it,” Leonardi says. “There’s no substitute for going out and trying the machine to make sure it performs the way you think it’s going to. It’s a big investment; make sure it’s right for you. Make sure it fits what you think it’s going to do for you.”