Wood chipper blades are essential for shredding wood, but they can become dull and need to be sharpened over time. Frequent sharpening of chipper blades is crucial for making sure they last longer, and the wood chipper can efficiently break down all kinds of plant debris.
If you are in the market for a new chipper or looking to replace your old one, you can check out our collection of certified wood chippers here.
In this guide, you'll learn how to remove your wood chipper blades efficiently and safely, and how to correctly sharpen them so that they can continue to provide superior performance. It's a relatively straightforward process, and it'll ensure your chipper will always be reliable at any time of need.
How Do You Know You Have Dull Blades? the Signs
Even when following manufacturers recommended sharpening times, blades can still become dull. There are a few ways to tell if you need to sharpen your chipper blades. First of all, the wood chips should be nice and thin. If they're coming out in large chunks or are thicker than usual, this is generally an indication that you'll need to get them sharpened soon.
Other indications include:
- An increase in engine noise
- when chipping seems to take longer than it should
- Inconsistent/increased hopper vibrations
- Poor quality chips with a stringy consistency
- Engine smoking or overheating
- Chipper no longer self-feeds
Related: How To Use A Wood Chipper.
Removing The Wood Chipper Blades
The first step in sharpening chipper blades is to remove them from the wood chipper. This can be done by following these simple steps:
STEP 1 - Turn Of The Wood Chipper
The first thing to do for any machine is to make sure it doesn't accidentally start it up while you're working on it. An accidental start could cause severe injury or even death.
For an electric wood chipper, it's as easy as turning off the wood chipper and unplugging the chipper from any electrical source.
For a gas-powered wood chipper, it's just as easy, though not intuitive, especially for new owners. You will need to disconnect the spark plug.
This is because gas-powered wood chippers and most small machines use centrifugal force to start the engine. When you pull the starter rope, it turns the crankshaft which then causes the spark plug to spark, igniting the gas and air mixture, causing combustion
an accidental rotation of the flywheel when removing the blades can cause the spark plug to spark and instantly start the wood chipper.
You can disconnect the spark plug by either unscrewing it from the engine or removing the boot that sits on its top.
Step 2: Remove The Feed Chute
The next step is to remove the feed chute/hopper.
For models that have a hinged chute, removal is unnecessary, and you only need to unscrew or unclamp one side of the hopper and flip it open.
If the feed chute is attached to the metal frame and is not hinged, you will need to remove the screws or bolts that hold it in place. You'll need a socket set or a wrench to unscrew the bolts and separate the hopper and housing.
You'll want to make sure you have a bucket or container nearby to place all the nuts, bolts, and washers that you remove so that nothing gets lost along the way.
Step 3: Unscrew the inspection plate
Open the wood chipper inspection plate to access the flywheel with the blades attached. You may also have to remove a flail screen if your model has one equipped.
This step might not apply for woodchippers with a hinged hopper as you will already have direct access to the rotor and blades.
In case your chipper is slightly different, check with the manufacturer manuals for the steps needed to access the blades.
Step 4: Remove the blades
Start by removing the bolts, nuts, and washers that attach the chipper blades onto the flywheel and rotor.
Use a wrench or the manufacturer-specified tool to work on the bolts. They might be a little tight, especially if rusty, so you might need to use a little extra force. Be careful not to slip while turning the wrench, as the blades could still hurt you.
Do not use grooved plyers as they could damage the heads of the bolts
TIP: Before removing the blades, take a picture of the blades so you can have an easy reference point on how they are installed, the orientation, and the bolt setup
Sharpening Wood chipper blades
Before you proceed to sharpen your blades, you should check whether they are the reversible type. If they are, simply flip each to the other side, rotate them (like you would with car tires), and reinstall.
If you've used both sides, or your blades aren't reversible, then it's time to sharpen them.
Step 1 - Choose A Sharpening Tool
A disc sander, an angle grinder, or a bench-mounted sander are all excellent options depending on which tools you already have in your garage and how often to use it. Some of the other standard sharpening tools include:
- Manual hand sander
- Belt sander
- Wet grinder
Different tools have different use styles, and you need to find the one that most suits your sharpening skills.
The belt sander, for example, is a fixed tool. It remains in a fixed position during sharpening, allowing you to sharpen and maintain the factory angle effectively. If you are using a hand sander, you'll have to secure the blade in place, so it doesn't move during sharpening.
STEP 2: Know Your Chipper Angle
The type of tool you choose is not as important as knowing the angle you need to maintain during the sharpening process –altering the angle on the cutting edge reduces the chipper's performance. This angle is usually stamped on the blade or in the manufacturer's manual.
STEP 3: Sharpening The Chipper Blades
The third step to sharpening a wood chipper blade is to select fine-grit sandpaper or a grinding wheel with very fine grit with a 400-grit or 1000-grit.
Using a fine grit allows you to sharpen wood chipper blades without removing too much material. This helps preserve the recommended factory angle, usually 30 to 45 degrees, and prevents the blade from overheating and losing its heat treatment.
If you are using a wet grinder, you need to prep the blades by taking the pitch off on all sides using a chisel, knife, scraper, or a similar device. Here are common steps when using a wet grinder:
- Set the miter at 90 degrees and the table at 45 degrees (or as recommended by OEM). You can use a protractor or an adjustable square to set your miter and table angles.
- For the best results, make sure the grinder is set towards the rotation of the cutting edge rather than away.
- Start sharpening by moving the tool back and forth with a consistent slow motion across the wheel. Do not put too much pressure. Repeat a few times to sharpen the blade perfectly.
- Continuously dip the blades in water with each pass to avoid the blades from overheating. You don't need to use the drip system –the catch tray is sufficient.
STEP 4: Remove The Burr After Sharpening
Burr is a residual piece of metal that forms on the blade surface as you sharpen it. If not removed, it causes premature dullness due to increased friction.
To remove the burr, get a finer grit than what you used for sharpening and use back and forth swiping motions to remove the burr. You can then brush or air off all the metal shavings and particles from the blade before reinstalling the blades
if you have a chipper with more than one blade, remember to balance the blades so that they both have equal weight
Step 5 - Balance The Blades
If your chipper has more than one blade, you will have to balance the blades. If the blades are left unbalanced, they will vibrate and cause the chipper to work harder, leading to unnecessary stress on the blade shaft, vibrations, and possible damage to your engine.
Factors That Affect Woodchipper Blades Sharpness
The type of wood being cut – Softer woods, like pine, take less time to dull a blade than harder woods, like oak. Twigs and small shrubs are also easier to shred and take less toll on the blades compared to larger branches.
How often the chipper is used – If you use it daily, then you can expect to need sharpening more often than if used weekly.
Debris entering the hopper - If a lot of debris enters the chipper blades, like rocks or metal, it can prematurely dull them. Make sure to clean the hopper as too much debris regularly will eventually cause damage to the edges.
Type of Blade - The more hardened and thick your blade is, the longer it will last. Thin blades are more susceptible to wear and tear.
Maintenance and Care - General maintenance of the wood chipper blades will go a long way in ensuring longevity. Ensure to clean the blades and the area around them after each use. well-maintained blades will keep the chipper working at its best.
Also check out our wood chipper collections including:
Wood Chipper Blade Sharpening; FAQS
How often should you sharpen your wood chipper blade?
Generally, chipper blades should be sharpened after every 25-50 hours of usage.
Different chipper blades have different usage, and you need to keep track of how often they get dull. Meaning, depending on the conditions, you may behave to sharpen earlier than the stated time or much later. However, if your blade starts to chew out rough, unshredded, or uneven wood chips, then it's time to consider sharpening it.
What angle do you sharpen chipper blades?
Wood chipper blades need to be sharpened at the factory recommended angle. The common sharpening angle for most wood chippers ranges between 20 and 45 degrees depending on the make, model, and brand.
How long do wood chipper blades last?
The lifespan of a wood chipper blade can vary based on the material you are cutting and how often it is used. Single-sided blades typically last 75 to 150 hours, while double-sided blades have double the lifespan of a single-sided blade and can generally last between 150 to 300 hours.
What are wood chipper blades made of?
Wood chipper blades are mainly made of premium steel allow that contains at least 8% chromium for hardness and durability. Some blades are also coated with titanium or other materials to prevent corrosion.
What is the difference between a single and double-sided wood chipper blade?
Double-sided blades have two sharpened sides and can be used by flipping them over to use the other side once one side gets dull. A single-sided blade only has one cutting edge and needs sharpening, or replacement once dulled, which is why they are cheaper than double-sided ones.
Wood chippers and shredders are an essential asset for any homeowner or landscaping business. By taking care of your chipper blades and sharpening them regularly, you can ensure smooth, clean cuts and less wear on the equipment. That is why you should learn how to sharpen chipper blades the right way without causing harm to you or the machine.
If you think the sharpening process is hard or complicated, it's recommended to take your blades to a professional machinist who has the experience and knowledge to get the job done right and without any damage.