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Skid Steer Stump Grinder

Skid Steer Stump Grinder

Looking for information on skid steer stump grinders? You’ve come to the right place. We have organized some important consideration when selecting a skid steer stump grinder. And of course, if you still have questions when you are done reading, we are ready to answer your call.

What is a Skid Steer Stump Grinder and what does it do?

Let’s start with the basics. A skid steer stump grinder is a skid steer attachment that uses the auxiliary hydraulic power from your skid steer to apply torque to a large flywheel with cutting teeth on it. This attachment can then be used to grind tree stump down.

A skid steer stump grinder is commonly used by landscapers, arborists, farmers and ranchers. Removing old and unwanted stumps may be necessary not only for aesthetics, but also to avoid fungus, diseases and pests. You may also want to remove stump when breaking new land for agricultural purposes.

Will my new Skid Steer Stump Grinder Fit My Skid Steer?

To begin your search, you should make sure that your skid steer is capable of handling the stump grinder you are considering.

Most modern skid steers will have universal quick attach couplers to hook up to attachments. This should be paired with a skid steers stump grinder with a universal quick attach as well. There is not normally any fitment issue with skid steer stump grinder couplers because the universal quick attach is very common and widely used in the industry.

Next, you should ensure that your skid steers has an appropriate auxiliary hydraulic system to run the stump grinder.

The obvious first step in this is to ensure that your skid steer has an auxiliary hydraulic system. You will have auxiliary hydraulic couplers on your skid steer if you do.

Less obvious though is if you have a case drain line. This is the “third” hydraulic line that is essential for many high flow hydraulic applications. If your stump grinder requires a case drain, you should ensure that your skid steer has one as well.

Each skid steer stump grinder will have an operational hydraulic flow range published by its manufacturer. Ensuring your skid steer is capable of providing the correct hydraulic flow is important to ensure the proper function of your stump grinder. Using a stump grinder outside of its published flow range may void your warranty and cause premature failure.

Lastly, if your stump grinder requires electrical connections, ensure your skid steer is equipped with an external electrical harness.

Not all stump grinders will require an electrical connection to operate. Often a standard stump grinder that does not have a “swing arm” will not require electrical inputs in order to operate.

If your stump grinder does require an electrical harness, the proper one should be selected to fit your machine at checkout. If you are unsure which one you need, you can always contact one of our team members.

Ideally, if you have an external electrical harness (“14 pin” connector or otherwise), the stump grinder will plug directly into it, and you will be able to use the built in controls in your skid steer to operate the stump grinders swing arm.

It should be noted though that isn’t always possible because some customers don’t have external electrical harnesses, and occasionally, some skid steers external electrical harnesses aren’t compatible with stump grinders (for example, some newer high flow Bobcats). In these cases we can offer customers a “universal controller” that plugs into the stump grinder and draws power from your 12V plug in, or directly from the battery. You then use a separate controller that mounts in your skid steer to operate the stump grinder.

Swing Arm or No Swing Arm?

Some skid steer stump grinders will come with a swing arm, while others will not. The swing arm allows the skid steer to stay stationary while the skid steer operator manipulates the swing arm back and forth to grind the stump.

The first main advantage to having a swing arm is that it limits the amount of trampled and compacted turf around the the stump by not having to have the skid steer moving back and forth multiple times. This make it a handy option for arborists working primarily on customers lawns.

Another advantage to having a swing arm is ease of operation for the skid steer operator. Being able to sit stationary and control the swing arm alone allows for more precision and efficiency. It also allows for added safety when working in tight quarters.

But what are the disadvantages to having a swing arm? Firstly is the higher upfront cost to purchase the swing arm model. You should also consider that your swing arm stump grinder will have more hydraulic and electrical components.

What Type Of Motor Should My Skid Steer Stump Grinder Have?

We need to have a quick look at what the ideal qualities would be for a skid steer stump grinder motor. 

Firstly, because we are trying to spin a flywheel that often weighs in excess of 1500lbs through a hard stump, we are going to need a lot of torque. Torque is going to be far more important than the speed of the flywheel. For example, having a fast flywheel that looses 50% of it’s energy when it contacts the stump won’t do us any good. A high torque, low speed motor is far more useful.

We also have to consider how smooth the motor is at controlling the flywheel at a wide range of hydraulic flow. This is specially important for low flow skid steers. Smooth control over the flywheel is far more difficult in low gallon per minute operations.

Another consideration is efficiency. Having a hydraulic motor that is only 70% efficient leaves 30% of your skid steers potential unused. This translates into slower grinding times and less work done each day.

With these goals in mind, we suggest buying a skid steer stump grinder with a radial piston pump. 

In fact, a radial piston motor checks all the boxes when compared to the often used “direct drive” geroler motor.

The radial piston motor has a higher displacement than many direct drive motors of similar output. The higher displacement allows the motor to produce high torque and maintain low speed (LSHT Motor), while the direct drive motors lower displacement means it has to spin at high speed with a lower torque.

The higher displacement also allows the radial piston motor to maintain smoother control in low flow applications. Radial piston motors also have efficiency as high as 97% while direct drive motors are known to be only 70% efficient.

So what’s the draw back to radial piston motors? For one, they are more expensive. This is largely because they are built with extremely tight valve clearances making the manufacturing process more expensive. Another draw back to the tighter valve clearances is also that the motor will have a lower contamination tolerance than a direct drive motor. Most customers will accept this draw back with a commitment to proper maintenance and cleanliness.

Skid Steer Stump Grinder Flywheels

The size of your skid steer stump grinders flywheel, as well as the number of cutting teeth and their placement will largely determine how well your stump grinder cuts through stumps.

The size of the flywheel usually increases with the size of motor and host machine. Having a large flywheel for the size of motor will give your wheel more inertia when it’s cutting allowing it to rip through stumps easier without slowing down.

Flywheels range in diameter, thickness and weight. Normally, however, 24” to 31” diameter, 3/4” to 1 1/2” thickness and any where from 1,000 to 2,000 pound flywheels are used for skid steer stump grinders.

The number and placement of teeth on a flywheel will range largely between manufacturers and models. It should stand to reason that the more teeth on the flywheel, the more cutting will be accomplished per rotation.

The teeth should be on both sides of the flywheel to allow for cutting in both directions. Some manufacturers will only put cutting teeth on the edge of the flywheel to save money, however, we do not recommend this set up.

Most manufacturers will offer the same teeth for their skid steer stump grinders. These teeth are normally carbide and reversible for extended life.

Rounding It All Up

The only corners worth cutting are made of wood when purchasing a skid steer stump grinder (pause for laughter).

A skid steer stump grinder is a very specific tool intended for one job only. Understanding how to get that job correctly and efficiently is the key to success.

Be sure to do your research. Ensure that the stump grinder you are purchasing is built to grind stump into next decade, and is not just a low cost example of a manufacturer cutting corners.

Contact Us For More Information

We are waiting to take your call. 1-866-990-SKID(7543).