When researching what to look for when buying a PTO Wood Chipper, it can sometimes be difficult to understand a specific features usefulness until you begin using the wood chipper at which point their value becomes quite evident. We’ve put a lot of hours on a lot of different wood chippers to learn which features and designs work best and compiled this list to help you understand the importance and purpose of each feature.
Some wood chippers are designed with a flywheel housing which does not open (closed housing). They instead utilize small cover plates to access and change blades, unjam material and for general maintenance and inspection of the flywheel area. In contrast, a wood chipper with a “clamshell” design means it has a split housing, which allows the user to easily hinge open half of the housing, providing much better access to the knives, bed plate and flywheel. If you’ve ever attempted to clean out a flywheel housing or change blades, you will most certainly appreciate this feature when the time comes to do one of these tasks.
This may be one of the most overlooked features we hear about with PTO wood chippers. It’s not until you try to take your wood chipper through a tight area in the bush or turn around on your property where you realize that a chipper can become like a large trailer as it swings and sways behind your tractor. Extra care and attention must be given so that it doesn’t bump into a tree or object. Secondly, it’s not until you decide to put your chipper in the corner of your shed, garage or barn when you realize how much valuable floor space it actually takes up. As an example, the floor space or foot print area of the WC68 is reduced by over 30% once the infeed chute is folded up.
Some wood chipper manufacturers that don’t adopt this feature will simply put the infeed chute on a steep angle as to minimize their foot print. This solves one problem, but unfortunately creates another. Feeding long or heavy branches into a wood chipper with an angled infeed chute can be challenging. The operator needs to lift and tilt the branch up over their shoulders to feed it into the chipper. Look for a wood chipper with a relatively horizontal infeed chute. Feeding branches into a wood chipper around waist height and horizontally is the most ergonomic method.
This may seem like an insignificant feature and one that is quite commonly overlooked. However, if you consider the fact that every single branch that gets fed into the hopper will make contact with this leading-edge area, it is imperative that it is designed in a way that doesn’t promote branch catches or hang ups. A leading-edge round bar would be the number one design, followed by bent hopper panel plate with a radius as number two and finally just a hopper panel with a sharp edge as one to avoid.
Some wood chippers will gear up the flywheel speed via a set of pulleys and belts. Wood chippers that do this need to incorporate a way of applying adequate belt tension to prevent under or over tension. Both of these scenarios could cause premature belt and bearing failures. The best practice for applying proper and adequate belt tension is an automatic belt tensioning system utilizing tension springs and a swing arm. The springs ensure a constant and adequate belt tension is maintained at all times. This design also makes changing belts quick and easy. Designs that do not adopt springs often require the owner to pay close attention to belt tension before and during operation. They typically require tools to manually adjust the belt tension. Again, applying the right amount of tension with this method can be challenging. What is too tight and what is too loose? Finally, changing belts with this type of design can be quite time consuming.
A hydraulic infeed wood chipper features a roller with teeth that is powered by a hydraulic system. The infeed roller will rotate, and the teeth will bite into branches and pull them into the chipper in a controlled speed and predictable manner. The infeed rollers typically have three (3) positions – Forward, Neutral & Reverse. This provides the operator with full control of how the branch is fed into the wood chipper and is a great safety feature. Furthermore, if a branch was to get jammed, it can easily be reversed out of the infeed hopper in a safe and controlled manner.
The larger the diameter of the infeed roller, the easier it will climb up and over the wood you feed into the chipper. Small infeed rollers are more difficult to get to climb up over branches on their own. Wood chippers with undersized infeed rollers often have an infeed roller lift assist to help lift the roller up and over larger material. The downside to this is that it is difficult to pull down on the spring-loaded lever with one hand and feed branches into the hopper with the other hand. It becomes quite a strenuous and awkward task especially when chipping wood for long periods of time. A good rule of thumb is a 1:1 ratio between roller diameter size and chipper capacity. As an example, an 8” capacity wood chipper should have no less than an 8” diameter infeed roller.
Flywheel weight can sometimes be misunderstood. “The bigger, the better” old adage isn’t necessarily the case here. Don’t forget that it takes horsepower to spin a flywheel, even if it isn’t chipping wood. The key in purchasing the right wood chipper is matching it to your particular tractors size and horsepower. This is the main reason you will see manufacturers carry various size wood chippers stating recommended horsepower ranges - one size doesn’t fit all.
A heavy flywheel can certainly have a lot of momentum and help with short peak loads (such as knots), but it will not help when long periods of work is required that is outside of the tractors horsepower capability. At some point, the flywheel RPM could slow down (momentum drops) if high peak loads occur, meaning the horsepower of the tractor will need to do the work directly. The other item to consider is flywheel RPM recovery time. If the flywheel slows down during the chipping process, the operator must stop feeding material into the wood chipper to let the flywheel recover to full RPM again. The quicker the flywheel RPM recovery time, the sooner the operator can begin to feed more material into the chipper.
Lastly, comparing flywheel weights between manufacturers can become confusing. Some manufacturers include all of the components that bolt to the flywheel – blades, shafts, pulleys as total flywheel weight. While other manufacturers provide the flywheel weight as the flywheel on its own – no components. Since all manufactures use steel flywheels, the best way to compare flywheels is by looking at diameter and thickness.
Naturally, the bi-product of the branches going into the wood chipper are the wood chips that exit the discharge chute. Depending on where you are on your property, you will certainly have a preference as to where you would like the wood chips to be displaced. A discharge chute that can be easily rotated 360 degrees and one that includes an adjustable chip deflector will allow you to position the chips in any direction and either close or far away from your working area. The combination of these two features will provide you with complete control over the location in which the chips land.
Two edges are better than one! Some wood chippers utilize blades with one cutting edge while others have two cutting edges. Blades with two cutting edges are referred to as “reversible blades” or “reversible knives”. This is a great feature as it’s essentially a second set of knives at no cost. You simply unbolt the existing blades, flip them 180 degrees and re-bolt them on.
Many tractor owners utilize a quick hitch or John Deere iMatch 3 point hitch attachment which allows faster hook ups to your various implements. If you have one of these, you will want to ensure that the chipper you purchase is compatible with quick hitch or iMatch. All Woodland Mills chippers are quick hitch and iMatch compatible.
The act of chipping wood is no joke. When you start feeding larger hardwood material through your chipper, the forces applied to the structural components can be quite substantial. Good sharp blades will help with this, but as the blades wear down the forces applied to the body of the wood chipper start to increase. When looking at wood chippers, be mindful of the general build and construction of the wood chipper. Steel plate thicknesses, shaft sizes, bearing sizes and overall weight are generally good indicators as to how well built the chipper is.