Commercial Wood Chippers – A Buyer’s Guide

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Now that you know what a woodchipper is, its subclassification into chipper, shredder, combo (combination chipper shredder), and tree grinder; as well as how it works, and the safety precautions you need to take when using this equipment; it is time to learn what factors to consider before acquiring one.

As expected, the type of woods that you want to break down, and what you intend to do with the chips is the overarching determinant of whether the woodchipper model suits your needs or not.

Also, there is a need to know that there are heavy-duty consumer-grade and commercial models that are built on vehicle frames with attached wheels (usually two) and a drawbar.

This allows them to be towed by vehicles while allowing for the woodchipper and IC engine to be fitted on the same frame. These heavy-duty models can be used for clearing debris in large farms.

The factors that you should consider when comparing woodchippers, or assessing the suitability of a particular model to meet your needs are explained below.

1. Chipper Capacity

As mentioned above, one of the first things to consider is the size of the wood that can be fed into the chipper.

The feed capacity is used to reference the size (particularly the diameter or width) of the wood limb that you can safely and easily push into the chipping mechanism.

The feed capacity is measured in inches (in) (and sometimes in millimeters [mm] for small-sized models). This capacity can range from 2inches for small models to 160 inches in industrial woodchippers.

The other consideration regarding chipping capacity apart from feeding capacity is the number of blades/flails in the chipping chamber.

As a rule of the thumb, the higher the number of blades, the better the chipping (efficiency). Even so, the blade quality remains an overriding consideration as a single high-quality blade can do better chipping than multiple poor-quality blades.

2. Reduction ratio

This is a nominal value of how much the chipper breaks down the wood limb into wood chips. It is referenced to the feed capacity and the average chip width, and it can be calculated as follows:
Reduction ratio = Feed capacity / average chip width (in inches)

The reduction ratio usually ranges from 10:1 to 20:1.

As a rule of the thumb, the higher the reduction ratio, the better the machine is at chipping.

This means that you should consider the reduction ratio as it gives you an idea of whether the wood debris would be reduced to chips that can suit your needs.

Nonetheless, chipper shredders do not have a fixed reduction ratio.

3. Type of Engine

woodchipper image

Woodchippers are classified into two types based on their engine types:

Electric-powered models are usually shredders that use electric motors whose power ratings range from 1-2HP and are suitable for chipping small and softwood debris. Also, as explained above, their portability is limited compared to the IC models.

Fuel-powered models can be used for heavy-duty wood chipping depending on engine power output and the flails in the chipping chamber.

Even so, they are heavier than their electric-powered counterparts, and most are fitted on towable wheeled frames, which also improves their portability and eases their transportation on roads.

Some small- to -medium-duty fuel-powered models are designed to allow a person to push them around the yard, and they are described as walk-behind fuel-powered woodchippers.

Your choice of engine type should be determined by the expected workload or future work needs.

Sometimes, the yard size can determine expected workloads, and by extension, the type of engine you should choose.

4. Engine Capacity

As explained above, the engine capacity determines how much power the engine can deliver to the blade shaft that spins the impeller.

This engine capacity is measured as displacement volume in cubic centimeters (cc). As a rule of the thumb, the higher the engine capacity, the higher the power output. Even so, the power output of the engine is measured in terms of horsepower (HP).

Therefore, when checking the chipper engine, you can use its engine capacity to determine its power output, if no HP rating is provided.

Almost all engines used in woodchippers are four-stroke IC engines.

You should also understand that higher power output means that more fuel will be burnt because the engine will have a larger combustion chamber as compared to engines with low power outputs.

Therefore, fuel economy also needs to be factored when choosing a fuel-powered chipper.

5. Power Rating

The following list roughly matches the power rating to the feed capacity, and it should be used as a general guideline:

  • 35mm feed capacity requires a model with a power rating of 2000–2200W.
  • 38–45mm feed capacity requires a chipper power rating of approximately 2500W.
  • 50mm feed capacity requires a chipper power rating of over 3300W.

You should choose a model whose power rating can handle your expected workload and sizes of wood limbs

6. Feeding mechanism

Usually, it is recommended that you should choose a model that supports self-feeding. This is because such models have better safety profiles as compared to models that require you to push wood into the chipping unit.

Even so, the feeding mechanism must be able to transfer your wood to the chipping unit, and therefore the weight and size of wood that you intend to feed into your chipper should be considered.

The feeding mechanism must be able to handle the wood load at the inlet, and for heavy-duty work on a woodchipper with long feed trays (or feed throat), grooved rollers are a suitable feeding mechanism.

7. Chipping mechanism

The chipping mechanism is the cutting tool used to reduce the wood into woodchips. As explained above, there are 3 types of chippers; drum, disk, and screw chippers.

The disk chipper uses the bladed disc system (rotating flywheel with blades) as its chipping mechanism, and it is suitable for producing fine uniform chips, even though it is noisy and prone to jamming.

The drum chipper uses the rotor system as its chipping mechanism, and some have weighted toothed wheels located between the feed throat and the impeller, and these wheels crush the wood before it is fed into the impeller.

This is common in heavy-duty drum chipper for chipping dry hardwood. Even so, this rotor system operates at lower rpm as compared to the bladed disc system.

The turbine system uses energy-efficient, spinning blade-shafts to rotate multiple bladed drums that chip dried hardwood.

You should choose a chipping mechanism that can handle the hardness of your wood debris, as well as chip the wood to your desired reduction ratio.

8. Construction

A lightweight, small chipper with a funnel-shaped supply chute and 2 back wheels should be able to withstand vibration and heat produced in the chipping unit, and this requires this chipper to be made using durable materials.

As expected, chippers need to have robust construction and must be made from strong materials that can withstand vibration and friction without wearing and tearing quickly. Likewise, the blades must be able to maintain their sharpness for long durations.

It is recommended that chippers are made from thick, welded steel, usually gauge 10 or gauge 16 steel.

9. Portability

As mentioned earlier, the chipper must be moved around the yard, and it is prudent that you acquire a model that has wheels.

10. Convenience Features

These are features that make the woodchipper easy to use, maintain, and service.

They include drawbars for towing, forward discharge chutes, electric starters, self-sharpening blades, integrated collecting bins, and even tilt-down hoppers.

You should look for features that can make your chipping task easy and hassle-free.

11. Warranty

High-quality models are usually supported by a guarantee that they will work as described in their manuals without failing for a particular period of time.

This guarantee is given as a warranty against factory errors and other errors that are not caused by the user.

Therefore, you should look for a woodchipper with a warranty.

12. Cost

After consideration of the above 11 factors, you should be able to narrow down your chipper choices. The last consideration is now the price as you can only acquire a chipper that you can afford.

It is prudent to purchase the best chipper within the price range that you can afford, instead of saving money by acquiring a model of questionable quality.