A Clear-Cut Decision
Tips for Selecting a PTO-Driven Horizontal Drum Mulcher
By Bill Schafer Aug 10, 2012
When it comes to right-of-way and land clearing, the equipment choice is clear-cut. Thatís because few machines offer the same level of performance, versatility and safety as PTO-driven horizontal drum mulchers. This makes them ideal 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, however, there are several more important choices to make. From cutting teeth options to the drive system, the machines can be configured many different ways to meet individual needs.
First Things First
Before getting too deep into drum mulchers, itís 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? By answering this question, a person can make the decision process a little easier. The type of application also 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 system is fine. However, 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 much 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 tough material.
Pick Your Teeth
After considering how the horizontal mulching drum will be used, itís time to think about options. The best place to start is deciding between swinging-hammer and fixed cutting teeth. The two types require different rotor configurations, so this decision needs to be made right away. Swinging hammer teeth are like heavy-duty flails. They swing freely on the rotor and use centrifugal force to produce a powerful cutting action. Unfortunately, some people have poor opinions about swinging hammer designs, due to bad past experiences. However, the issues that once hindered the machines have been resolved in some of todayís products.
The main frustration when it comes to swinging hammers is maintenance. On early models, each row of hammers rotated on a single shaft. Therefore, if one hammer needed to be replaced, all of the hammers in that row had to be removed. To make things even more difficult, the shaft was often nearly impossible to
remove, due to rust, damage or wear. Individually replaceable hammers are the answer to this problem.
Through a system developed by Loftness (a manufacturer of attachments for agricultural, forestry and land management), each hammer can be taken on and off in a matter of minutes, and replacement can easily be done in the field. This simple enhancement has leveled the playing field to once again make swinging hammers an attractive option for mulching drums.
The major benefit of swinging hammers is the 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 also ideal for tractors with less than 105 hp, since small tractors donít have the power needed to keep a rigid-tooth rotor spinning through tough material. Furthermore, swinging hammers are recommended for material less than 6 in. in diameter. Although they are capable of mulching larger trees, the process may take longer since 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, and there are no moving parts to wear. This type of rotor is typically recommended for higher-horsepower tractors and for mulching material larger than 6 in. in diameter. Although there are a few varieties of fixed teeth, most manufacturersí 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 they donít require sharpening. The downside of the standard tooth, however, 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.
Additionally, they require less power and leave a finer finished product. The blades are reversible, but they do require routine grinding in order 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 arenít as sharp as hardened steel or as durable as standard carbide teeth, but they can be extremely effective in the right conditions. Theyíre best suited for loamy soils with less rock.
After deciding on the 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 also available with a shear bar. It increases efficiency and provides a cutting edge to help reduce particle size. Also, it 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 either manual or hydraulic adjustment, and it is used to push standing trees away from the tractor as they are being mulched. Therefore, if using the machine primarily for mowing, this option may not be needed. The mulching door is usually offered with manual or hydraulic adjustment as well. Again, if using the mulcher mostly for mowing, the manual option may work just fine, as 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 some features that can further reduce maintenance. For instance, some manufacturers offer an automatic belt tensioner, eliminating the need to routinely adjust tension as the belt wears. The automatic tensioner uses a spring-loaded system to ensure smooth, consistent power transfer and maximize belt life.
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.
Bill Schafer is a product manager for Loftness, based in Hector, Minn.†