Tips for Selecting a Power Take-off Driven Horizontal Drum Mulcher
By Bill Schafer
When it comes to right-of-way and land clearing, the equipment choice is clear-cut. That's because few machines offer the same level of performance, versatility and safety as power take-off (PTO-) driven horizontal drum mulchers. They are useful for many professional contractors looking for a cost-effective method for mulching thick grass, brush and trees. In many cases, they may already own a suitable tractor for other jobs.
Once the decision to purchase a horizontal drum mulcher is made, there are several important choices to make. From cutting teeth options to the drive system, the machines can be configured many different ways to meet individual needs. To help sort through the options, you need to know how to get the most mulcher for your money.
First Things First
Before discussing drum mulchers further, it's important to first identify how they will be used. These units can be pushed or pulled behind the tractor for mulching or mowing, but will the operator actually use the machine for multiple applications, or just one?
The type of application helps determine what type of tractor will work best. For mowing applications where the mulcher will mostly be pulled, any tractor with a standard three-point hitch, PTO shaft and operator protection will work. If the mulchers will be pushed for a large portion of the time, reversible platforms are preferable. Swinging the seat around to face the rear of the tractor provides a more comfortable and natural position for the operator to work for extended periods of time.
Hydrostatic tractor drives are also recommended over mechanical drives for applications where the unit will be pushed behind the tractor. Mechanical transmissions can be jerky, and a tractor may stall if the mulcher is forced into a large tree too quickly. On the other hand, hydrostatic transmissions help the operator slowly drive the mulching drum into difficult material.
Pick Your Teeth
After considering how the horizontal mulching drum will be used, it's time to think about options. Decide between swinging-hammer and fixed cutting teeth. The two types require different rotor configurations, so this decision needs to be made promptly.
Swinging hammer teeth are like heavy-duty flails. They swing freely on the rotor and use centrifugal force to produce powerful cutting action. And, issues that once hindered the machines have been resolved in most current products.
The main frustration with swinging hammers is maintenance. On early models, each row of hammers rotated on a single shaft. If one hammer needed to be replaced, therefore, all of the hammers in that row had to be removed. To make things more difficult, the shaft was often impossible to remove because of rust, damage or wear.
Individually replaceable hammers are the answer to this problem. Through a system developed by Loftness, each hammer can be taken on and off in minutes, and replacement can easily be done in the field. This simple enhancement has leveled the playing field to make swinging hammers an attractive option for mulching drums.
The main benefit of swinging hammers is forgiveness of the design. If one of the hammers suddenly strikes a rock or large tree, it will buckle, rather than staying rigid and stopping the rotor. This forgiveness makes swinging hammers well suited for less experienced operators. These products are useful for tractors with less than 105 horsepower, since small tractors don't have the power to keep a rigid-tooth rotor spinning through tough material. Swinging hammers are recommended for material less than six inches in diameter. Although they are capable of mulching larger trees, the process may take longer because the hammers are likely to give way under the heavy load, rather than maintain the ideal cutting angle.
The other option is to use fixed teeth. Unlike swinging hammers, there is no give to fixed cutting teeth. This means they always stay at the optimum cutting angle; there are no moving parts to wear. This type of rotor is typically recommended for higher-horsepower tractors and for mulching material larger than six inches in diameter.
Although there are a few varieties of fixed teeth, most manufacturers' standard carbide teeth are generally similar in design. Benefits of standard carbide teeth are durability and cost efficiency, based on longer life. They are made to withstand moderate rock contact without breaking and don't require sharpening. The downside of the standard tooth is that its chisel point with rounded top prevents it from working as quickly as teeth with sharper edges.
The next type of fixed tooth offered by most manufacturers is a hardened steel blade. These blades have a sharp edge, allowing them to mulch material more effectively than any other type of cutting tooth. In addition, they require less power and leave a finer finished product. The blades are reversible, but they do require routine grinding to enjoy the advantages of a sharp tool.
For those who want the combination of a sharp edge and low maintenance, planer carbide tips are also available. They aren't as sharp as hardened steel or as durable as standard carbide teeth, but they can be extremely effective in the right conditions. They are best suited for loamy soils with less rock.
After deciding on cutting teeth, consider the components of the cutting chamber. Most manufacturers offer counter teeth, which are welded inside the housing to enhance the grinding performance, but some units are available with a shear bar. The Tree Hammer model from Loftness, for example, offers a shear bar that covers the counter teeth and acts similar to the chipping anvil on a wood chipper. It increases efficiency and provides a cutting edge to help reduce particle size. It also minimizes wedging from root balls or other debris in the tapered chamber.
Other horizontal drum mulcher options include a push bar and hydraulic mulching door. The push bar is typically offered with manual or hydraulic adjustment, and it is used to push standing trees away from the tractor as they are being mulched. If primarily using the machine for mowing, therefore, this option may not be needed. The mulching door is usually offered with manual or hydraulic adjustment as well. If mostly using the mulcher for mowing, the manual option may be best because it can remain closed during operation to direct the mulched material toward the ground.
The final options for selecting a horizontal drum mulcher revolve around the drive system. Although PTO drives are known for reliability, there are features that can further reduce maintenance. Some manufacturers offer an automatic belt tensioner, eliminating the need to routinely adjust tension as the belt wears. The automatic tension uses a spring-loaded system to ensure smooth, consistent power transfer and maximize belt life.
The machines typically come standard with a single belt drive but usually have a second drive as an option. This is usually reserved for higher horsepower tractors, such as those rated with at least 125 horsepower.
Requests for PTO-driven horizontal drum mulchers have grown in recent years because of their extreme versatility, durability and productivity. Interest has also increased because the discharge trajectory is more controlled than alternative mulching equipment, helping to improve safety. With the right set of options, you can experience the same success for mowing and mulching applications.
About the author: Bill Schafer is product manager for Loftness Specialized Equipment, which manufactures the VMLogix line of vegetation management equipment. Schafer has been with Loftness for more than 20 years and has focused specifically on the vegetation management industry for 12 years.