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13 Jul 2017

Don’t Underestimate the Need for Chipper Maintenance


p class=”art”>It can be easy to look at the heavy-gauge steel and the massive horsepower that chippers possess and think they’re indestructible. Chippers are incredibly tough — they need to be to stand up to the extreme duties they perform — but they’re still machines at heart, powered by motors and pumps, belts and bearings. If you think of your chipper as just a big block of steel, that’s probably what you’re going to end up with. For it to perform the way it was designed, you need to maintain it properly.

Staying sharp

Bruce Bartling, sales manager with Cal-Line Equipment in California, conducts regular chipper maintenance trainings on the West Coast. His company is a dealer for Bandit Industries, but Bartling says that, when it comes to chippers, many maintenance tasks are the same regardless of brand. Blade maintenance, for example, which he says is one of the most important chipper maintenance tasks. “That’s the heart of the machine,” says Bartling. “A chipper is a cutting device, so everything has to be sharp to work properly. If it’s not cutting properly, you can have a lot of associated problems that you may not think are related. It may not pull in the material the way it should; it may bog down the engine – everything is just having to work harder.” He compares it to using a chain saw with a dull chain: a chain saw (or chipper) can be brand new and have plenty of power, but if it’s not sharp, it could be outperformed by an older, smaller unit that is sharp.

How to know when sharpening is required? The answer to that depends on what’s being chipped, and how careful the crew running the machine is. For starters, hard, dry wood will wear blades out faster than soft wood. Constantly chipping big wood also speeds the wear process. Finally, “a lot of time, the wear on the blades can be caused by getting dirt and rock in there; crews are raking stuff up off the ground and not realizing they’re getting that stuff in with the wood,” says Bartling. The cutter bar or anvil can also be worn down this way, though more slowly. “It will round off, and it needs to be a square edge,” he says.

Chipper knives and anvil or bed knives are often overlooked in terms of maintenance, says Casey Gross, product sales manager at Morbark. “Often we see customers flip their chipper knives, or install new ones, then overlook setting the anvil or bed knife to the chipper knife,” he notes. “In order for the anvil or bed knife and chipper knife to work at optimal performance, it is important to ensure the anvil or bed knife has a 90-degree cutting edge and is properly adjusted to the chipper knives.”

A daily filter check on a chipper at Graf Tree Care in St. Charles, Illinois. Scott Turney, fleet and facility manager, says that as a reminder about the importance of greasing, he printed pages from the manuals of the chippers the company uses showing all of the grease points and hung them on the wall of the shop.

Fluids, filters and more

Gross says there are many critical components on a chipper, including the engine, driveline, chipper disc or drum and the hydraulic system. “While it important to maintain all of these systems, the most overlooked is the hydraulic system maintenance,” he states. “The hydraulic system is the heart of the chipper’s operating system to run the pumps, motors, valves and cylinders. It is often overlooked because as long it is working, it is out of mind.”

One relatively easy way to keep this system running smoothly is through regular filter changes. “While changing the hydraulic fluid is not always necessary, periodic filter changes would benefit these systems greatly to avoid contaminants from damaging the hydraulic system components,” Gross explains, noting that some dealerships have the technology within their service departments to flush and recycle the existing oil to reduce the costs replacing the oil. Of course, it’s also important to regularly check and change engine oil and oil filters.

Some of the other most-overlooked maintenance items involve the engine air intake system, says Lucas Graham, lifecycle manager with Vermeer. On a basic level, that means inspecting the air cleaner filter restriction gage (if equipped). “If your machines don’t have a restriction indication, carefully remove the air cleaner cover and inspect the air cleaner element. Make sure to pay special attention to ensure it gets reinstalled correctly,” Graham advises. He says it’s also important to inspect the charge air coolers that have been added to many Tier-3 engines. “The charge air coolers can triple the number of intake hose connects compared to a normally aspirated engine. Each of these connects needs to be inspected, along with the tubing and elbows for cracks, loose hardware, and proper sealing on a regular basis.”

While some of this type of maintenance is best done in the shop, there’s plenty that a crew can do even out in the field. “Things like cleaning the air filters and keeping the radiator clean are really important,” says Cal-Line’s Bartling. “Greasing is something you definitely need to be able to do. And when it says ‘daily,’ it’s referring to eight hours of use,” Bartling emphasizes.

Scott Turney, fleet and facility manager with Graf Tree Care in Illinois, says that as a reminder about the importance of greasing, he printed pages from the manuals of the chippers the company uses showing all of the grease points and hung them on the wall of the shop. “Those have to be checked and greased daily,” he reiterates. In fact, that’s one of the maintenance items that Turney asks crews to check when they’re out on jobs during the day. “I equipped every chipper we have with a toolbox and a grease gun,” he explains. “If the chipper is running all day long, they can check it mid-day to make sure the grease is OK.”

One note of caution: “For some bearings over-greasing can be just as damaging as not greasing enough,” says Vermeer’s Graham.

Other things to keep an eye on

“There aren’t a whole lot of moving parts on a chipper, but what does move is key,” says Bartling. That means keeping an eye on things like hydraulic relief pressures, clutches and belts. Particularly on larger chippers that are handling bigger material, “you need to make sure you stay on top of your clutch adjustment, or you can burn your clutch up very easily,” he says. “On a brand-new chipper, it’s all set, but then you have a break-in period where you need to stay on top of it.”

Moving beyond the chipper itself, trailering maintenance is overlooked, says Bartling. There’s a lot of weight on a single axle, for instance, and the heavy use can eat away axle bearings. “That’s something that nobody ever looks at,” he says. “Yearly, depending on how far you’re driving, those should be opened up and repacked. But a lot of times people won’t do anything until there’s a problem. We see chippers every so often on a flatbed because the wheel came off.”

Turney with Graf Tree Care advises checking trailer wheels on a weekly basis to see if the bearings are loose, noting that he has heard of one instance where a bearing seized up and the wheel broke off, creating a bad accident.

It’s important to uncouple the chipper from the truck each night, and then reattach it in the morning, Turney says. Leaving the chipper hooked up all night “puts unnecessary wear and tear on the truck springs,” he points out. “Check the lights daily, and the trailer plug that plugs into the back of the truck. And, if you can, if you’re in an area where it’s salty during the winter you should rinse off the trailer — and the whole machine — daily to help prevent corrosion.”

On that note, Turney makes clear that cleaning the chipper is part of maintaining it. That includes checking the chutes at the end of each day: “You need to look for any debris that’s left in there; when it’s wet, it soaks up water just like a sponge. First, it can create a jam if gets too big. And, second, it can cause corrosion if it’s overlooked for a period of time.”

Graham adds that it is important to take time to clean off any accumulated wood chips and sawdust inside the engine compartment, as well as around the fuel tank fill neck and electrical connectors. “I recommend starting with a leaf blower first, since the lower air pressure has less force and will prevent forcing dirt and moisture further into bearing and electrical components compared to high pressure air, or pressure washing,” says Graham.

Finally, for late-model chippers equipped with EPA Tier-4 Final diesel engine technology, there may be some additional maintenance chores to perform.

“Operators may have Diesel Exhaust Fluid reservoirs to maintain and, depending on the engine manufacturer, Diesel Particulate Filters to watch over,” says Gross with Morbark. “It is important to understand how these systems work to ensure the engine continues operating at peak performance.”

Keeping track of it all

Gross says a great way to keep up with maintenance is to make it a daily part of the job. “It is important for operators to do a daily maintenance check and walk-around of the chipper every day before operating the unit,” he states. “A quick five-minute trip around the machine each day could save thousands in unnecessary repair costs.” As noted earlier, this walk-around should include an inspection of things like the trailer-to-truck connections, trailer lights, clutch engagement, drive belt tension and chipper knives, as well as a check for loose bolts, fasteners and fittings, or damaged hydraulic hoses.

Maintenance should be tracked on a log for each chipper, documenting the date and the number of operating hours at the time of each service. Gross says this can be done the old-fashioned way on paper, or on a smartphone or tablet, which can also be programmed to send reminders about specific maintenance when it’s needed.

Greasing is an easy, but critical, maintenance item on chippers. One note of caution: “For some bearings over-greasing can be just as damaging as not greasing enough,” says Vermeer’s Lucas Graham.

Keeping up with maintenance pays off both in terms of the performance and longevity of the chipper, and the safety of those operating it, says Gross. For example, the poor feeding performance that results from dull chipper knives “may result in operators performing unsafe work practices such as trying to kick material into the machine,” he says, noting that operators kicking material into a machine feet-first accounts for 48 percent of chipper-related iHampton Roadsuries and deaths. “With the root cause being poor maintenance, these accidents are completely avoidable.”

“The number one concern with not performing regular chipper maintenance is safety,” agrees Graham. But the other major reason to keep up with maintenance is also crucial to any tree care business, he adds: avoiding significant unplanned machine downtime for a major repair.

The post Don’t Underestimate the Need for Chipper Maintenance appeared first on Tree Services.

12 Jul 2017

The Importance of Chipper Maintenance


p class=”art”>Of all the tools that the modern arborist uses, the chipper is often the largest, loudest and most complicated. Brush chippers need to operate long hours with little to no downtime. Unless you are an extravagantly well-equipped crew, you rarely have an extra to use in a pinch.

To be effective, efficient and safe, chippers must be maintained and cared for on a regular basis. This article will break down chipper maintenance into manageable chunks (pun intended) and help establish regular checks, adjustments and repairs. Like all complex jobs, chipper maintenance should be a routine series of tasks performed in a routine way.

There are numerous brands of chippers on the market today, and manufacturers strive to make machines that are productive, safe and affordable. There are a number of ways to achieve these goals, and infinite variations on them. As such, all chippers have characteristics in common, but no two brands are exactly the same. We will explore some overall strategies and tips, but in no way can we cover every detail of the chipper you use daily.

For that, you must refer to the bible of chipper maintenance and operation, the owner’s manual. If you bought it new, your chipper comes with one by law. If you bought it used, you are required to get one. Either way, OSHA/ANSI require one on the machine during use. The OM has all the details you need to check and adjust your machine per the original specifications.

For our purposes, we will break the chipper down into three sections. First is the chassis. Most chippers are towed behind another vehicle. The chassis allows it to move safely from one job to the next. Think of it as the trailer your machine sits on. The next part is the power plant. This is the engine that powers the knives and spits the chips out the chute. Finally comes the core, or everything in between the power plant and the in-feed chute. These three areas have separate concerns deserving separate consideration.

Hitch attachments should be inspected every time the chipper moves. Photo: Anthony Tresselt

Hitch attachments should be inspected every time the chipper moves. Photo: Anthony Tresselt


Just latching on and going down the road is no way to tow anything. Before hooking up, go over the chassis systematically from front to back. Starting at the front of the chipper, inspect the hitch, chains and electrical hookup. Look for broken, bent or missing pieces, weld cracks, excessive rust and excessive wear. What defines excessive? Always refer to the OM for specific metrics, but don’t forget the little voice in your head. If it looks wrong, err on the side of caution. Avoid the tragedy of losing your trailer while going to the job by never allowing the condition of you chassis to deteriorate. For efficiency and safety’s sake, the jack stand should be operational and the correct size.

Moving to the rear of the vehicle, make sure any traffic cones, toolboxes, fenders, mud flaps or other things attached to the chipper are secure. Also make sure an appropriate, serviceable fire extinguisher is present and operational. Take a close look at the decals provided by the manufacturer. Make sure all the warning and operational ones are present and legible. These serve as valuable reminders to the crew.

Safety decals provide valuable information. Photo: Anthony Tresselt

Safety decals provide valuable information. Photo: Anthony Tresselt

Check the tires for proper tread depth and air pressure. If the chipper is equipped with a braking system, check for proper functioning as per the OM. If any of the frame surfaces are used as steps or footholds, make sure they are covered in anti-slip tape and are oil and dirt free. Check all lights and assure proper functioning. As with all chipper maintenance, a checklist is vital to ensure items are checked in a routine manner.

Power plant

Regular engine service is critical for safe operation. Most likely your chipper has a separate OM for the engine. Follow it for service intervals, lubrication types and replacement part guidance. However, a daily inspection is also necessary. Be sure to look for fluid leaks, missing bolts, loose belts and excessive debris nestled up close to the engine block. Maintain the proper fluid levels and replace the filters as stated in the OM. Keep the radiator cleaned to avoid overheating. Regularly clean the air filter. Chipping brush and wood is dusty business. Use a high-quality fuel source and additives as needed for climatic conditions.

Chipper maintenance Photo: Anthony Tresselt

Chipper maintenance Photo: Anthony Tresselt


The core is what makes a chipper a chipper. Any accident can be boiled down to a root cause, and chipper accidents are no exception. Any chipper manufacturer will tell you that improper maintenance and operator error are the root cause of the majority of chipper incidents. Poor maintenance leads to improper equipment function. Poor function leads to anger and frustration. This, in turn, leads to bad judgment and rushed actions.

The core of chipper maintenance is safety through properly operating machines. Adopt an attitude of safety as the basis for chipper use and upkeep. Well-running machines are easier to use, last longer, generate more revenue and are prone to fewer accidents. You can’t expect your crews to safely operate a poorly working machine.

Lock-out, tag-out

Before any maintenance or adjustment begins, the chipper needs to be shut down, with no parts in motion. Manufacturers install a number of safety devices to ensure that access to rotating belts, disks, knives and drums is restricted if in motion. Make sure these are all operational. As a further check, attach any keys to locked areas or panels of the chipper to the machine’s ignition key. Doing this means the machine must be turned off with the keys removed from the ignition before maintenance can begin. The keys should then reside on the person who is performing the work. This is a basic lock-out, tag-out procedure and should be used as a minimum precaution. Expand it as your equipment and work environment demands. Also, never check for hydraulic leaks without eye protection and covered hands. High-pressure hydraulic fluid can penetrate the skin or eyes and cause serious iHampton Roadsury. Even with the machine off, latent pressure can still be high.

Here is a manufacturer approved repaired stress crack. Photo: Anthony Tresselt

Here is a manufacturer approved repaired stress crack. Photo: Anthony Tresselt


Chippers notoriously shake, rattle and roll when processing material. This constant vibration leads to cracks, breaks and fatigue on all parts of the system. Bouncing down the road on the way to the job can also cause breakage. Look for signs of wear and tear at weld seams. Scan for loose or missing bolts, nuts and/or rubber mounts. Check the hydraulic hoses for chafe marks, loose fittings and leaks.

Vibration stress can rear its ugly head in any number of ways. It is particularly tough on rusted areas of the machine. The weakness of the metal oxidation is further stressed by vibration, torsion or other shock loading. Address rusted areas before they get out of hand. By far, the best way to prevent vibration stress is to prevent vibration. That leads us to our next topic.

Keep it sharp

The leading cause of excessive chipper vibration is dull knives and worn anvils. These cutting surfaces wear through use and must be constantly maintained. Dull knives start a cascading effect on the whole system. Not only does vibration increase, but the drive belts, clutch and bearings are stressed. This, in turn, makes the engine work harder to chip the same amount of material and causes a decrease in the workload, which can lead to frustration and bad choices. Even a properly used chipper that is fed only the cleanest material will dull. Check the knives frequently and rotate to sharp surfaces when necessary. Check your OM for the minimum knife width and never use knives that are less than this. As a knife is sharpened it becomes narrower across the long axis. This increases the space between the anvil and the cutting edge of the knife. If this distance gets too large, then even a sharp knife cannot cut material and instead tears it. Imagine a sharp pair of scissors with a loose pivot bolt. Also check the knives for cracks or other irregularities. Replace knives as needed.

As they are sharpened, knives get shorter. Photo: Anthony Tresselt

As they are sharpened, knives get shorter. Photo: Anthony Tresselt

The anvil is the second piece of the cutting equation. Anchored to the body of the chipper, it adjusts in relation to the knives on the disk or drum. While not sharp, the anvil must have a clean, square, smooth edge to process material properly. Think of the unsharpened side of a set of scissors. Anvils wear more slowly than knives, but still need periodic examination and adjustment. Refer to your OM for the specifics. Conditions, materials and operator habits will dictate how often the anvil needs to be serviced.

No single article can discuss all the possible scenarios and maintenance issues for every chipper in use today. However, there are many similarities and procedures that can, and should, be implemented by all brush chipper users to ensure safe, productive operation of any machine. Use what we have discussed as a starting point, expand on it as necessary. Follow your OM. Keep the safety devices operational. Keep the cutting surfaces sharp. Implement and follow sound operating and maintenance procedures and processes routinely, and your brush chipper will work as long and hard as you and your crew.

Editor’s note: This article was originally published in February 2011 and has been updated for accuracy and comprehensiveness.

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