Learning how to sharpen a reel lawn mower is a key skill for any owner of these quiet, eco-friendly machines. Sharpening a reel mower’s blades restores its scissor-like cutting action, giving you a healthier lawn without engine noise or fumes. A dull reel mower will tear grass instead of cutting it cleanly, leading to a brown, ragged lawn that’s more susceptible to disease.
This guide will walk you through the entire process, from assessment to final adjustment. You’ll learn the tools you need and the steps to follow for a perfect cut. With a little time and effort, you can maintain your mower’s performance for years.
How To Sharpen A Reel Lawn Mower
Before you begin sharpening, you need to understand the basic components. A reel mower cuts grass by trapping a blade against a sharpened bed knife. The spinning reel, with its multiple helical blades, passes closely over this stationary knife. This shearing action is what creates the clean cut.
When either the reel blades or the bed knife become dull, the cutting action fails. The grass is pinched and torn. Sharpening involves refining the edge on both of these critical surfaces to restore that precise scissor action.
Tools And Materials You Will Need
Gathering the right tools before you start makes the job smoother and safer. You don’t need a fully equipped workshop, but a few specific items are essential.
- A reel mower sharpening kit (often includes lapping compound and a backlap handle)
- Adjustable wrench or set of open-end wrenches
- Fine-grit sharpening stone or honing stone
- A flat file for the bed knife
- Clean rags
- Light machine oil or WD-40
- Safety glasses and work gloves
- A sturdy workbench or table
Safety First: Preparing Your Workspace
Always prioritize safety when working with sharp tools. Start by finding a clean, well-lit area to work, like a garage or patio. Clear the space of any clutter to avoid tripping or knocking things over.
Put on your safety glasses and gloves to protect your eyes and hands from metal filings and sharp edges. Ensure the mower is completely clean of grass, mud, and debris before you start disassembling anything. A clean mower is easier and safer to handle.
Disconnecting The Reel From The Wheels
Most reel mowers have a drive mechanism connected to the wheels. You must disengage this so the reel spins freely for sharpening. Consult your mower’s manual, but typically there is a lever or clutch to pull. On some models, you may need to remove a pin or clip. This step is crucial for the backlapping process later on.
Assessing The Blade Condition
Not every dull mower needs a full sharpening. First, perform a simple test. Lift the mower so the reel is off the ground. Spin the reel slowly and carefully slide a piece of plain paper between the reel blade and the bed knife at several points along the length.
If the blade slices the paper cleanly, the edge is likely still good. If it crumples or tears the paper, sharpening is needed. Also, look for visible nicks, dents, or rolled edges on the reel blades. These will require more attention with a stone.
The Sharpening Process: Step-By-Step
There are two primary methods for sharpening a reel mower: backlapping with compound and manual stone sharpening. Often, you will use a combination of both for the best results. We’ll start with the most common technique.
Step 1: Adjusting The Bed Knife
The bed knife must be perfectly aligned before you sharpen the reel. Loosen the bolts that hold the bed knife in place on the mower’s frame. Gently tap the bed knife until it makes light, even contact along the entire length of the reel. You should hear a slight “hiss” as you spin the reel.
Retighten the bolts carefully, checking that the contact remains even. This step ensures that when you sharpen, both surfaces will meet correctly. An uneven bed knife is a common cause of poor cutting after sharpening.
Step 2: Backlapping With Lapping Compound
Backlapping is the process of applying an abrasive compound to the reel and spinning it backwards against the bed knife. This hones both surfaces simultaneously. It’s excellent for maintaining an already decent edge or for minor dullness.
- Apply a thin, even strip of coarse-grit lapping compound to the cutting edge of the bed knife.
- Attach the backlap handle to the reel axle if your mower has provisions for one. Otherwise, you may need to carefully turn the reel by hand using the blades themselves (wear thick gloves).
- Spin the reel backwards for 30-50 revolutions. The compound will grind away microscopic metal, sharpening both edges.
- Wipe away all the used compound thoroughly with a rag and some oil. Any residue left behind will cause rapid wear.
Step 3: Manual Stone Sharpening For Nicks And Dulls
If the blades have nicks or are very dull, backlapping alone won’t be enough. You’ll need to use a sharpening stone on each individual reel blade. This is a meticulous but rewarding process.
Mark one blade with a marker so you can track your progress. Place the fine-grit stone against the beveled edge of the first blade. Using a consistent motion, stroke the stone along the blade, following its original angle. Do the same number of strokes on each blade to maintain balance. This ensures the reel spins smoothly without vibration.
Sharpening The Bed Knife With A File
While the reel is off, you can also dress the bed knife. Use a flat file, holding it perfectly flat against the top surface of the bed knife. File in one direction only, using long, smooth strokes. Your goal is to create a clean, sharp edge, not to remove a lot of metal. Check frequently with your paper test.
Step 4: Final Cleaning And Reassembly
After sharpening, it is critical to remove all metal particles. Use a rag soaked in light oil to wipe down the reel, bed knife, and the mower’s interior. These particles are abrasive and will accelerate wear if not removed.
Re-engage the drive mechanism you disconnected earlier. Apply a few drops of oil to the reel bearings and any other pivot points. This keeps everything moving freely and prevents rust.
Step 5: Setting The Final Cutting Height And Clearance
The final adjustment is setting the correct clearance between the reel and the bed knife. This is often called the “snap” test. Adjust the bed knife so that a piece of newspaper is cleanly cut when the reel is spun, but a thin feeler gauge (about 0.001-0.003 inches) can slide between them without being cut.
This tiny gap prevents the blades from binding while still allowing a clean cut. Adjust your mower’s roller or wheels to set your desired cutting height. Test the mower on a small patch of grass to ensure it cuts cleanly before mowing your entire lawn.
Maintenance Tips To Extend Time Between Sharpenings
Regular care can significantly prolong the sharpness of your blades. A little maintenance after each use goes a long way in preserving that perfect edge you just worked hard to create.
Clean After Every Use
Always hose off or brush away grass clippings and dirt from the reel and underside of the mower. Let it dry completely before storing. Wet grass left on the blades can promote rust, which quickly dulls the metal.
Store Properly
Keep your mower in a dry place like a shed or garage. If you must store it outdoors, use a waterproof cover. Moisture is the enemy of sharp steel blades. Consider applying a very light coat of oil to the blades before long-term storage.
Perform Regular Paper Tests
Get into the habit of doing the simple paper test every few mows. Catching a dull edge early means you might only need a quick backlap session instead of a full manual sharpening. This saves you alot of time and effort in the long run.
Frequently Asked Questions
How Often Should I Sharpen My Reel Mower?
This depends on how often you mow and the size of your lawn. For an average suburban lawn mowed weekly, a thorough sharpening may be needed once per season. However, using lapping compound for maintenance every 4-6 mows can keep the edge keen much longer.
Can I Sharpen A Reel Mower Without Taking It Apart?
The backlapping method allows you to sharpen the mower with minimal disassembly. You typically only need to disengage the drive mechanism. For minor touch-ups, this is very effective. For major nicks or an very dull mower, more disassembly for stone work is usually required.
What Is The Difference Between Reel Mower Sharpening And Rotary Mower Sharpening?
They are fundamentally different. A rotary mower has a single, heavy blade that spins at high speed to impact and cut grass. Sharpening it involves balancing and grinding that one blade. A reel mower relies on the precise shear action between two sets of blades, requiring alignment and honing of multiple contact surfaces.
My Mower Still Doesn’t Cut Well After Sharpening. What’s Wrong?
The most likely issue is incorrect bed knife alignment or clearance. If the bed knife is not parallel to the reel, contact will be uneven. Go back and carefully readjust the bed knife, ensuring light, consistent contact along the entire length. Also, check that the reel bearings are not worn, causing wobble.
Is It Worth Paying A Professional To Sharpen My Reel Mower?
For a basic sharpening, doing it yourself is cost-effective and satisfying. However, if your mower has significant damage, bent blades, or worn bearings, a professional service with specialized grinding equipment may be the best solution. They can also perform a precision grind that is difficult to achieve at home.