While a lot of factors go into choosing a chipper, knowing what you want to do with the end product and what size trees you will be processing are two good places to start.

If there are markets in your area for landscape mulch or compost material, you might not want to consider a chipper at all. A horizontal or tub grinder will produce that kind of shredded end product. “But if you are just trying to get rid of the wood and you have a market for fuel chips or if you’re just going to blow it on the ground and use it for erosion control, then a chipper is better,” says Dan Brandon, marketing director for Morbark. “The chipper is a little bit faster than the grinder, too.”

Two basic types of chippers – disc style and drum style – are available. If you want to sell your chips to be used as fuel or made into paper or plywood, you should probably use a disc-style chipper, which produces a better quality, more uniform sized chip, Brandon says. Many contractors are selling chips to power companies, which use them as fuel. “It’s worth your while to chip the material and truck it to the power plant,” Brandon says. “You get rid of a waste product and get compensated some for it, so in the end, you come out ahead.”

But if you are chipping only to reduce material, the drum-style chipper has an advantage because the infeed opening is generally larger and the machine can easily process trees with multiple limbs and material that is more disoriented and stringy, Brandon says.

Tracked machines are also useful if you are not interested in capturing the chips and have a large area to clear or a long, narrow site such as a power line or gas line project.

When deciding what size chipper you’ll need, Brandon recommends taking stock of the largest diameter trees you’ll be processing and buying or renting a machine with capacity for the next size up. That way you won’t be taxing the chipper’s engine, hydraulics and moving parts to the max. “It’s not good on any machine to feed it its full capacity all day long,” he says. “It’s like buying a car and driving it 100 mph every day. It’s just not going to last.”

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TIP: Make sure the discharge shoot is not pointed toward people or objects that could be damaged.

Beware of the infeed area
Because of their speed and power, chippers are fairly dangerous pieces of equipment. As with any machine, those operating a chipper should read, understand and follow the instructions in its accompanying manual. “This holds true for the first-time user and for those who have been running chippers for years,” says Leslie Kinnee, spokesperson for Bandit. “Even seasoned operators need a refresher.”

Several manufacturers also provide videotapes that explain how to safely operate the machines.
When using a chipper, you should wear a hardhat, safety gloves (not the gauntlet type), earplugs and safety glasses. Loose clothing, jewelry and watches should not be worn.

The infeed area is one of the most dangerous locations on a chipper. “That’s where the job of the machine is to grab material and pull, and it can’t differentiate between people or jackets or a hat or glove or wood,” says Chris Nichols, environmental product manager for Vermeer. To help address this problem, Vermeer is offering a new feature called a bottom-feed stop bar that allows the operator to shut off the feed automatically in emergency situations
by striking the bar with his leg.

Don’t hand feed a large chipper that is designed to be fed by a loader. Know where the machine’s emergency shutdown mechanism is located and how it works. You should also keep the worksite clear, your visibility lines open and make sure bystanders are not wandering around.
Pay close attention to where you are sending chips as well. “They’re coming out at the other end at a pretty high speed,” Brandon says. “You don’t want people getting hit by a stream of chips.”

TIP: Stand to the side of the infeed hopper. This will allow you to walk away without passing through the path of the material.

Steering clear of common pitfalls
To increase productivity and minimize wear and tear on your machine, avoid these frequent mistakes:

· Not changing dull knives. You should inspect knives daily to make sure they are sharp and undamaged. “If you want to process a certain type of material, or want to have a certain size end product, one of the things that’s really going to determine that is the condition of the knives,” Nichols says. Dull knives will produce a heavier, stringier and inconsistent end product that will prevent you from getting your trucks as full as you would like, increasing the number of trips they will have to make. Dull cutter mechanisms also cause more vibration throughout the machine.

· Feeding dirt, stones or metal into the machine. “Chippers need fairly clean material,” says Ken Patterson, vice president of Packer Industries. Putting rocks, dirt or metal in the machine will cause the cutting knives to wear out prematurely. In addition, metal objects and stones can become dangerous projectiles.

· Forcing material larger than the chipper’s capacity into the machine.

· Improper engagement of the cutter mechanism. For example, engaging the clutch at high idle or having the engine rpm too high and trying to engage the clutch plates or start the cutter mechanism. This can be hard on driveline components.

· Not cleaning the machine. Sawdust and dirt will pile up on the chipper and around its engine. You should blow off this debris once or twice a day. If you don’t, and then shut down the machine at the end of the day and leave the site, heat from the engine can ignite that wood and the flammable fluids inside the chipper.

· Neglecting maintenance. Set up a preventive maintenance program and follow it consistently. “That will make for a machine that operates exactly like you expect it to operate and you end up with the result on your jobs that you were looking for,” Nichols says. See the box below for a basic maintenance outline.