Identify Your Grinder Goals

It's possible to spend as much as $750,000 or more for a large, high-horsepower grinder. Given that kind of cash outlay for a single piece of equipment, you don't want to have any regrets about the one you ultimately choose.

Models cover the spectrum from small, niche market units rated at less than 100 hp to those upwards of 1,000 hp. Some of the largest machines top 1,200 hp with openings as large as 15 ft. Coupled with more features across all size ranges, the opportunity to enhance your productivity is increased - and so is the opportunity to make a costly mistake.

"We go through quite a lot of questions with customers," says Chris Edmonds, Morbark. "We try to learn as much as we can about their goals - what they're trying to accomplish, what type of end product they want to make and what sort of volumes they expect. There's quite a learning curve before we start recommending individual machines to anyone. Contractors may have an idea of what they think they need. But that might not be the best option. They may not be aware of other options that might be available to them."

Tub or horizontal?
The first step typically boils down to choosing between a tub grinder and a horizontal grinder. Since their entrance into the marketplace just a decade ago, some manufacturers indicate sales of horizontal grinders have grown to the point where they now outnumber tub grinders at a rate of 2:1. But that doesn't mean there isn't still a place for both.

Because they are gravity fed and have large-diameter openings, tub grinders are very efficient at chewing away at large, unwieldy debris such as stumps and root balls. A tub grinder's shortcomings are typically related to material length, which is limited to the depth of the tub.

"Tub grinders are good choices for jobsites where you knock down trees, grub out the stumps and pull brush into piles with front-end loaders," says Dan Brandon, Morbark.

Tub grinders have also had a reputation for throwing debris. However, many manufacturers have addressed this problem by adding safety mechanisms to prevent debris from "popping out" of the top of the grinder.

"A lot of contractors believe horizontal grinders are safer," says Mark Rieckhoff, Vermeer. "But that's a misconception. That's why we have designed safety features for both types of grinders, such as the Thrown Object Deflector on horizontal grinders and Thrown Object Restraint System on tub grinders. Both systems have been designed to help reduce the quantity and distance of thrown objects from either grinder."

Horizontal grinders are well-suited for grinding long lengths of material, such as whole trees measuring 40, 50, even 60 ft. They excel in this application because you don't have to spend extra time cutting material into segments.

"Overall length and diameter are important considerations when selecting a grinder," says Rieckhoff. "If the material to be ground is longer or larger than the machine can handle, the operator has to give thought to how to pre-process it so it can be efficiently fed into the tub or placed onto the in-feed conveyor of a horizontal grinder. Without cutting to length long material, or shearing larger diameter material such as root balls, the operator will waste time in trying to manipulate it until it is of an adequate size to feed on its own."

Is bigger better?
Horsepower ratings garner a lot of attention when selecting a grinder. Mid-range machines are popular choices due to their balance between productivity and maneuverability. "Our 500- to 700-hp 3680 is the backbone of our grinders," says Troy Grover, Bandit. "It's an easy size for people to work with and it's easy to move around."

But the trend toward "bigger is better" is evident in the introduction of continually higher horsepower units. For example, Bandit offers a larger 860- to 1,000-hp 4680 horizontal grinder. And about a year and a half ago, Morbark introduced its 1,200-hp Model 1600 tub grinder.