The Basics: Chippers and Shredders

Chippers and shredders have been around for many years, and they are becoming more popular again as the trend toward recycling grows. Depending on your own lawn care needs and your local disposal facilities, chipped or shredded yard debris can be composted, turned in as yard waste at your local recycler or landfill, or used as mulch around your yard and garden.

Large commercial chippers grind up everything up to and including small tree trunks. Small electric shredder-only units are limited to chewing up leaves and twigs. Thus, most homeowners prefer a combination chipper-shredder. Some models are capable of chipping wood up to 3 inches in diameter. A chipper vac, a unit that looks a lot like a mulching push lawnmower, vacuums up leaves and twigs and mulches them for disposal.

In a combination chipper-shredder, branches are fed into a chute and are cut into chips by one or more steel chipper blades. Leaves and twigs are fed into a hopper, or bucket, at the top of the machine and are shredded with flails, or hinged steel blades, which rotate rapidly. The unit may include screens that filter the chopped up leaves. Debris that is too large to pass through the screens is re-circulated so it can be shredded again. The chips exit through a chute, often into a collection bag.

Small, stationary, electric chipper-shredders are available for the smallest tasks. Towable models that sport up to 10 HP engines will assist homeowners with bigger jobs.

Warranties on chipper-shredders vary, but 2 or 3 years seem to be typical.

Five Key Questions You Need the Answers to Before You Shop:
1. What do you plan to chip or shred? If you simply want to shred up the leaves and small twigs that litter your lawn, driveway and other surfaces, you may be happy with a small electric shredder. It will be more lightweight and less expensive than a combination chipper plus shredder or any gas model. But you will be limited to using it within 100 feet of an electrical outlet because most experts suggest that that is the practical limit of power cord extensions. If you have regular pruning chores and other larger debris, you will probably favor a chipper-shredder. And if you mostly need to clear your lawn of leaves and twigs, take a look at a chipper vac, the unit that looks like a lawnmower but sucks up and mulches small yard waste.

2. Do you need a gas or an electric model? As noted above, an electric model will be more lightweight and smaller, but its range of effectiveness is just 100 feet from a power outlet. A gas model will be more portable, and you can push or tow it, depending on the model, to wherever you need to clean up. A gas engine may provide the power that you need to accomplish your chores. On the down side, gas models are heavier to move.

3. What and how much do you have to chip or shred? Do you just need to shred leaves and twigs for mulch? Look at a shredder-only unit or a small electric chipper-shredder. Do you have trees and large bushes to prune? Is there a lot of vines and other debris to dispose of? Look at a chipper-shredder capable of doing both. If your job is beyond these choices, you'll need to look further and find a commercially rated unit.

4. How big is your yard? The size of your yard may dictate a lot about your choice in a chipper-shredder. If you have a small yard, you may want a stationary electric unit, which means you bring the debris to the unit to be processed. If you have a large yard, you will need a portable model and a way to move it. Some models can be pushed by hand and some can be towed by a tractor or truck.

5. How big is your budget? Wood chipper-shredders are relatively expensive outdoor power tools. Smaller, electric models are the most economical, but not if they can't handle the job at hand. Generally, the larger the yard waste a unit can effectively chip or shred, the higher the cost will be. You'll need to find the balance between cleaning up the yard and cleaning out the checkbook.

How to Shop

You'll find that several reputable manufacturers produce chippers-shredders in a wide variety of electric and gas models designed especially for the homeowner. But you may have to visit several stores in order to find models to compare. Chippers-shredders aren't as common as leaf blowers and many other outdoor power tools.

The most important considerations in choosing a chipper-shredder are power and RPMs (revolutions per minute) among models. Horsepower ranges from 1 to 10 HP on homeowner models. Generally, the more horsepower, the stronger the engine, and the heavier a task you can accomplish. The faster the blades turn, the more efficient the cutting will be.

Next, check to see how many blades the unit uses for chipping and how many knives it uses for shredding. More blades and knives usually mean a better cutting system. A good unit may have two blades and 8 or 12 shredding knives.

The manufacturer will tell you what reduction ratio to expect. The reduction ratio refers to the volume of debris before and after chipping or shredding. Be aware, however, that the reduction ratio may include air space. Obviously, unchipped or unshredded debris does not stack nearly as efficiently as chopped or shredded debris.

As you are shopping, learn what is included with each model. Does it include a collection bag? How large? Does it include a tow hitch? Pneumatic tires? A blower for loading debris into your truck or trailer? Or are these extras available as options if you need to add them? If you will be moving the chipper-shredder by hand, does it have a good handle for doing so? And does it balance nicely on its wheels for easy pushing? Does the model include a clutch to disengage the blades from turning when not in use? If you are looking at a gas model, how does it start?

Chipper-shredders can be dangerous power tools. Compare the safety features offered with each model before your purchase. And use your common sense when you operate the machine. Know the danger zones of the model you choose, and keep your hands and feet away from them. They will include the chute, the hopper, the exhaust and all of the moving parts. Use the machine only for chipping and shredding approved materials (organic yard waste) and don't feed it anything larger in diameter than recommended by the manufacturer. Keep the discharge area clear. Keep others away while you are using the machine, and wear ear and eye protection. Shut the machine down immediately if you hear a loud noise. You may have a clog that needs to be cleared. Don't use your hands to clear a jam; use a stick. And always wear safety glasses.