Application Tips: Chippers

The first thing you’ll want to consider when selecting a chipper is the size of the material you’ll be putting through the machine. Once you’ve established the largest diameter tree you want to chip, plan on buying a machine that will handle a little more.

If you’re going to be hauling away trees more than 12 inches in diameter, for instance, you’ll probably be chipping 12-inch trees most of the day, which would be tough on a chipper with a 12-inch limit, says Kevin Covert, sales and marketing manager for Rayco. You could increase the life of your machine by buying the next size up – a 15-inch chipper.

Another decision you’ll need to make is how you want to feed the chipper, says Dan Brandon, marketing manager for Morbark. You can feed a chipper by hand or with a loader, or you can buy a machine equipped with a grapple.

Knowledge of the sites where you’re going to use the chipper is also important. “Will it be easy to gather material and bring it to the unit?” asks Chris Nichols, environmental sales manager for Vermeer. “Does the unit need to be able to go off road and travel to the material?” If you prefer to have a mobile rather than stationary chipper, tracked machines are available. These units may best suit your needs if the majority of your jobsites are in areas where driving a truck and towing the equipment would be difficult, says Colleen Hall, Midwest sales representative, Bandit. Tracked chippers also give you the advantage of being able to work regardless of the weather and resulting ground conditions.

The type and consistency of the end product you desire may be critical to your selection process, and some machines are better than others with different materials. Having dealers demonstrate multiple machines is the best way to find out what end product a chipper will produce in your conditions, Nichols says. (As a starting point, see page 66 for more information about the two basic chipper types – disc style and drum style.)

You’ll also need to decide if you want a chipper with a manual feed wheel or load-sensing hydraulic feed rollers. With manual feed wheels you turn a knob to regulate how fast the chipper pulls in brush, speeding up for light material and slowing down for larger diameter trees. Load-sensing hydraulic feed rollers automatically stop and let the engine catch up if it bogs down. This feature is standard on most large chippers, and is an option on many small units.

Buy a chipper with the largest possible in-feed opening. With a wide in-feed opening, you won’t have to cut as many, or possibly any, branches off trees before you feed them to the chipper. Hand-fed chippers, for example, have in-feed openings that range from 6 to 20 inches wide. If your employees have to delimb trees in order to put them through the chipper, “what you’ll have is a guy taking twice as long to cut as a guy who feeds the whole tree into a 20-inch machine,” Covert says.

At the jobsite
Covert recommends buying at least one tracked chipper and support equipment with tracks so you’ll be able to operate regardless of ground conditions. You need to be able to work even if it’s raining or, if you’re located in the North, the ground is thawing in spring. Make sure your stump grinders are fast enough to stay ahead of site prep contractors, who can get impatient when it’s time to move their equipment to a job and it’s not ready. “Once you fall behind your schedule, it’s very difficult to catch up,” Covert says. “Know your contractors. Know your time tables. And know what equipment you need to complete the job under any circumstances.”

These are noisy machines, especially when processing dry wood, so consider not chipping early in the morning if you are working close to a residential area.

Chippers have an appetite for wood, not metal. Be on the lookout for nails and steel brackets that could damage the machine or dull the blades.

If you are using a disc-style chipper, keep the anvil adjusted. Stringy material will create a rat’s nest if the anvil is not tight fitting, says Dave Majkrzak, vice president of engineering, TerraMarc Industries. Check anvil clearance at least weekly and anytime chip quality is not what you think it should be.

Make sure blades are sharp and bed knives are properly adjusted as well, says Sal Rizzo, owner of Salsco. How often you sharpen blades should depend on the volume of work the chipper does and the amount of dirt on the trees and branches. Inspecting blades at the end of each day is a good idea.

Staying safe
Chippers can be dangerous so making sure your employees are educated about how they work and what to watch for is essential. Your machine’s operating manual will give them this information.

While having a drug-free workplace is always important, this kind of work demands it. “When you’ve got guys hauling chain saws and dropping timber, you want to make sure they’re doing it with a clear head,” Covert says.

Salsco chippers have a decal saying the manufacturer suggests having an operator stand by the chipper and control the feed handle at all times while it’s operating. “That’s one way to help prevent accidents,” Rizzo says. “If I was running the company, that’s what I’d do.”

Workers are exhausted at the end of the day, and just tripping near the machine could lead to injury. Rizzo suggests rotating your staff throughout the day so workers take turns monitoring the machine.

See the checklist below for more safety advice.


Disc and drum:
How they work: The chippers on the market today are designed to be versatile and work in various conditions and applications. As long as the size of the machine is matched to your job you can expect similar results from drum and disc chippers, says Chris Nichols of Vermeer. That being said, he adds that having a machine demonstrated at one of your sites will give you the best data to support your decision.


Safety guidelines

  • Do not operate a chipper alone.
  • Block the tires before operating.
  • Disengage the clutch before starting the engine.
  • Make sure the discharge chute is pointed away from people and buildings and is locked into position.
  • Keep hands and feet out of the in-feed hopper while the chipper is running; use a wooden pusher paddle to feed short material.
  • Do not wear loose clothing; it could get entangled in a branch that could pull you into the chipper.
  • If there’s any extra noise or vibration, stop immediately and check the chipper for damage.
  • When using a chain saw, wear protective clothing such as chaps for your legs in case you accidentally rest the saw against them.
  • Wear a hardhat, ear protection and safety glasses or a face shield.