Don’t Buy a Drum Mulcher Attachment Until You Watch This Machine Heads Video

Editor’s Note: This Machine Heads video is part one in a four-part video series on drum mulching attachments for skid steers and track loaders. MH editor Wayne Greyson discusses these gnarly brush cutters with experts like Caterpillar, ASV and Loftness. Here are parts two and three. Both have great insights on buying, operating and maintaining a drum mulching implement.

So, as the owner of a compact track loader, you’ve got the Swiss Army knife of construction equipment. The do-it-all, go anywhere, multi-talented tool carrier on two tracks. Truthfully, the compact track loader has outgrown its name. These are no longer just loaders. They are versatile tool carriers that become whatever the job needs them to become. In the North American market, we typically use these machines for multiple purposes. But in other sectors, CTLs have become so good at other jobs and so productive that in other markets there are CTLs in use as dedicated cold planers, trenchers, graders and (the focus of this story) brush cutters.

If you’re looking to unlock even more use — and revenue — out of your track loader by doing some land clearing or land management work, it likely means you’re looking to upgrade to or invest in a new drum mulcher. Because of its versatility, the drum mulcher has become the centerpiece of just about any land management operation, but how do you go about picking the right one for your needs? Watch that video above or read below.

What Is a Drum Mulcher Attachment?

Loftness rooftop hydraulic cooler.

Like the CTL, the drum mulcher itself is a Swiss Army knife. Using a spinning drum full of sharp teeth or blades, a drum mulcher can be lifted and lowered by your CTL to process just about any brush or vegetation you’re looking at bringing down — from high grass and other small material, all the way up to medium-sized trees upwards of 12 and even 16 in. in diameter. Plus, this attachment allows you to either blow and go — just get what’s standing up down on the ground and move on — or, with another pass, the drum sucks all of that material on the ground back up and processes it further, allowing you to mulch the material into a finer finish.

Drum mulchers come in different sizes ranging anywhere from 59 in. in cutting width all the way up to 84 in. and offer differing features such as variable torque motors, load-sensing motors, hydraulic deflectors and bite-limiters. But generally, the way manufacturers of these attachments segregate their lineups is based on the machine you’ll be mating the mulcher to.

What Type of Track Loader Do I Need to Run a Drum Mulcher?

The good news is that no matter the size or power of your compact loader, there’s a drum mulcher for you. The real difference between models — as is often the case with construction equipment — is productivity. How much can you get done in as little time as possible? As a rule, the dividing line for mulching is a host CTL with 75 hp. If the CTL you’re looking to mulch with is a 75 hp or below machine, you can outfit it with a drum mulcher that will be productive enough for light or occasional mulching.

But if you’re looking to do full-time mulching or know that you want to handle no matter what Mother Nature throws at you in as little time as possible, you’ll need a CTL with engine power north of 75 hp. For instance, Loftness’ Battle Ax lineup offers two sizes of mulcher: the light L Series and the standard S Series. Light drum mulchers are meant to be paired with a machine in the range of 30 to 70 hp. The standard Battle Ax on the other hand is meant to be paired with a machine in the 50- to 150-hp range.

Yanmar Compact Equipment brand ASV delineates its lineup in a very simple fashion. ASV offers the SD Series and DC Series of forestry mulchers, each with two models. However, these models are only designed for use with ASV’s 67-hp RT-65 CTL or above. ASV notes that it recommends the RT-75 as a 50/50 or 70/30 mulching split, with the machine being used 30 percent of the time as a mulcher. For full-time forestry work, ASV recommends moving up to the 132-hp RT-135 machines.

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How to Calculate Hydraulic Horsepower

FAE BL4 SSL forestry mulcher

The reason engine horsepower matters so much with hydraulic flow-hungry attachments is hydraulic horsepower. To find your machine’s hydraulic horsepower, you can use this equation:

Hydraulic pressure (psi) x hydraulic flow (gpm) ÷ 1,714

But where does engine horsepower factor in, you might be asking. Well, hydraulic horsepower can never exceed an engine’s ability. In addition to the hydraulics, the engine is powering the fan, alternator, A/C, and so on. So, if your hydraulic horsepower can never exceed your engine’s ability, and it’s pulling way more than double duty, you want as much engine horsepower as you can get if you’re going to be using attachments that demand a lot of hydraulic horsepower.

You want the maximum engine horsepower to ensure that, in addition to the fan, alternator, etc,. the engine has enough headroom to provide the power needed through the hydraulic system to transfer all available power directly to the mulcher. Let’s use the ASV RT-135 as an example. This machine delivers up to 4,060 psi. Multiply that by its max flow of 50 gpm, and you get 203,000. Divide that by 1,714, and you get 118 hydraulic hp that can be sent directly to the attachment. Because hydraulic flow is a major component to the hydraulic horsepower equation, some lineups refer directly to hydraulic flow rather than machine horsepower.

Caterpillar offers a wide variety of drum mulchers, and its model numbers indicate their capability. For example, the HM 115 breaks down like this: The 1 at the front of the model number means that it is a standard flow mulcher. The 15 at the end indicates it can achieve a 1.5 meter cut. Meanwhile, the 200 models are high-flow models, the 300 models require Cat’s High Flow XPS CTLs, which provide up to 32 gpm, and the 400 models require XHP or XE hydraulics that provide up to 40 gpm.

For Serious Forestry Work, You Need a Seriously Outfitted CTL

As we mentioned before, higher horsepower means higher hydraulic flow. When you pair high horsepower with high hydraulic flow, you get more available hydraulic horsepower for the drum mulcher to use. If you know you’re going to do a lot of mulching or other land management or forestry work, it’s important to start with a properly equipped, high horsepower, high-flow-capable CTL with the proper amount of cooling and protection from flying debris.

A forestry-specced CTL can always do dirt work, but a dirt-spec’ed CTL isn’t always an efficient match for forestry applications due to the sheer amount of hydraulic horsepower and, crucially, hydraulic cooling, these machines have available. For instance, ASV’s forestry machines have cooling packages that can take 100 percent load 100 percent of the time up to 118 degrees. Aftermarket, roof-mounted coolers for dirt-spec’ed machines are an option, but regardless, it’s important to consider your machine’s hydraulic cooling capability as well.

Those 400 model drum mulchers from Cat are designed for the company’s top-of-the-line 299D3 XE CTL equipped with a debris package and auxiliary coolers. If you want to be competitive in mulching, the minimum in terms of machine spec, you’ll want to consider is a machine with at least 36 gpm of hydraulic flow and 3,500 psi.

You also want proper cab protection. Drum mulchers dive head first into debris-filled environments and whip chunks of vegetation, wood and sometimes rocks hiding beneath all of that vegetation around at high speed. Sometimes that stuff leaves the drum footprint, and you want to make sure you have a polycarbonate door and windows to protect yourself while you operate but also a machine with the proper ROPS and structure protection as well.

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Carbide Teeth vs. Knives/Chisel Teeth on Drum Mulchers

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The other big consideration to make when it comes to drum mulchers is teeth. Drum mulchers are typically offered with three types of tooth options: carbide, flat-blade, and pointed blade. Carbide teeth are popular because they do a great job at bringing material down while also boasting a long wear life with little to no maintenance. Carbide teeth basically beat material into submission. Because these teeth knock the material down rather than cutting it, the end result is processed material with a stringy consistency.

But let’s say you want a finer material for use as landscape mulch or material that will decompose faster. You can achieve that with carbide teeth but with most mulchers you’ll need to close the front door of the mulcher and then back over that material and drag the drum through it a second time to break it down a bit more. So, in general, the downside to carbide teeth is that if you want finer material, you have to spend more time and more passes to achieve it. That’s where chisel or knife teeth come in.

These teeth are sharp, hence the “knife” name. They bite into material like a sharp axe and instead of beating it apart, cut vegetation into finer material. Flat-blade teeth are best at turning vegetation into neat, uniform size chips. Pointed knife teeth are helpful in splitting tough, fibrous material. The downside to these sharp knife-like teeth is that, like an axe or a knife, they need to be sharpened regularly to remain effective.

Do I Need a Bite Limiter or Depth Gauge?

The final major component of drum mushers you’ll need to consider is whether you’ll go with an open drum or a bite limiter design. An open drum means there is nothing between the drum and vegetation you’re going after. In most cases this design will give you the most knockdown power and the quickest result in terms of getting vegetation on the ground. A bite limiter, or depth control ring, on the other hand, does just as its name suggests: It limits the amount of material fed into the drum.

A bite limiter can be useful for those new to operating a drum mulcher because it keeps the attachment from taking on too much material and stalling out. When it comes to trees, the bite limiter is limiting the amount that the teeth can drive into the material. In viney or brush-type material, it makes sure that it the attachment moves slowly through he material and doesn’t overwhelm the drum.

A bite limiter or depth control ring design drum is typically paired with chisel or knife teeth as those teeth are sharper and therefore can eat through material more quickly than carbide teeth. In other words, those teeth can process material so quickly, a bite limiter can be a good idea. Carbide teeth, on the other hand, are typically mated with open drum-style drum mulchers. This is a good point to mention the design of the Loftness Battle Ax drum mulchers. All of Loftness’ Battle Ax mulchers have a bite limiter or, as Loftness calls it, a depth gauge. Loftness says what sets its depth gauge apart from typical ring-style bite limiters is that they aren’t overly limiting, allowing them to be used effectively with either knife or carbide teeth.

Because of this, the Battle Ax mulchers benefit from a two-stage cutting chamber with shear bars on the top and rear of the drum head. This means that with a Battle Ax, you can use carbide teeth and get finer produced material after one pass than you would without this two-stage chamber. For those who want a set it and forget it option with carbide teeth, the Battle Ax is definitely worth a look.

If you’re looking for even more info on brush cutting attachments for compact track loaders, maybe check out some of these archive stories we’ve produced on drum mulcher implements:

Wayne Greyson is the Machine Heads editor for Compact Equipment.