In Brief: How to Sharpen a Reel Mower
Reel mowers can be sharpened by back lapping or by hand. Back lapping is a type of maintenance for the blade. Remove one wheel, apply a valve grinding compound, then spin the blade backwards for a few minutes to maintain the blades. Sharpen the reel by removing it, holding it still, and sharpening each blade individually.
Reel mowers provide a clean cut with their scissor-like blade setup. Because of how the blades work, dulling or corrosion can throw the mower out of balance quickly. Sharpening the blades of a reel mower puts it back into top shape for your yardwork.
By learning how to sharpen a reel mower, you can keep your yard looking great without sending off your mower for expensive maintenance and blade work.
2 Ways to Sharpen a Reel Mower
You can do one of two things to sharpen a reel mower. Either perform routine blade maintenance by back lapping or sharpen a blade that’s too dull. Always try back lapping first, because it is a less invasive process with lower risks of ruining the blade.
Method 1: Back Lapping
As part of regular maintenance, back lapping helps you keep your blade in better shape without constant sharpening. It’s not an effective method for worn or damaged blades, but it’s great for putting the edge back on the reel.
- Step 1: Preparation
To back lap a reel mower, you to access the reel and disconnect the drive mechanism. In most reel mowers, this involves removing the reel cover and removing one wheel. If your mower does not have a reel cover, move directly to taking off the wheel.
Both reel covers and wheels are easy to remove. Look for the securing bolts and undo them. Remove the pieces carefully. Only one wheel needs to be removed to access the driving bolt.
The driving both is where the engine interacts with the axle to spin the reel as the mower moves. This bolt should be clearly visible when the wheel is removed. If you don’t see a bolt in line with the axle on the reel, try removing the other wheel to see if it’s on the other side.
Once you have access to the driving bolt, apply valve grinding compound to the tips of each blade. Apply it liberally on every blade from edge to edge.
Example valve grinding compound>
- Step 2: Sharpening
Back lapping is done by spinning the coated blade backwards. You can either use a hand tool or a power tool to spin the reel via the drive bolt.
Attach your tool to the exposed bolt and spin it the opposite direction from the cutting direction. You can determine the cutting direction by spinning the wheels and observing which way the blades naturally spin.
Continue spinning the reel backwards for a few minutes. Reapply the valve grinding compound as needed. By spinning the reel backwards, you are putting and edge back on the scissor blade to allow smooth cuts. You’re also grinding away burrs, defects, corrosion, and other imperfections.
- Step 3: Washing the Blades
Do not use the blades to cut directly after back lapping. Thoroughly wash the valve grinding compound off the mower and dry it before you use it again.
You can wash the compound off with water from a hose. Take the disassembled mower outside and rinse it with a hose until no more compound is visible on the blades. Make sure to spin it a few times to expose all sides of the blades to the water.
Inspect the blades before you finish washing. Operating your mower normally with value grinding compound still on the blades may cause the blade to dull faster.
If you want to clean it manually with a rag, do this carefully. The blades of a reel mower and sharp and can cut your hands. Wear leather gloves for protection and use a thick, wet rag.
- Step 4: Reassembly
If you washed your reel mower with water after back lapping, allow it to dry completely before reassembling it. Attach each piece back in reverse order of how you removed them.
Start with the wheel or wheels that you removed. Then, reattach the reel cover. Attach each piece securely so it won’t fall off while you’re mowing.
Test your blade by slowing spinning the reel to cut a piece of paper or grass. A clean cut without tearing shows that your blade is sharp and ready to use.
See an example of back lapping here:
Method 2: Individual Sharpening
Reel mowers rarely need to be sharpened. However, it is a possibility that the blades need to be sharpened. If you’ve already tried back lapping and the blades are still not cutting properly, try sharpening the blades individually.
Sharpening your reel mower may not be possible at home. If you do not have the right tools or experience to sharpen the blades properly, you may want to send it to a professional instead.
Step 1: Removing & Securing the Reel
In most reel mowers, the reel can be removed for sharpening. Consult with the owner’s manual for your particular mower to see if your reel can be removed or not. Most reels are removable by taking off the protective cover and unbolting the reel. It should lift out if it’s removable.
If you can remove the reel, take it out and secure it down with a clamp or any other mechanism to hold it completely still while you work. For reels that are not removable, use a clamp or a block of wood to secure the blade in place and avoid injury.
Wear a pair of leather gloves when sharpening to protect your hands. Avoid grabbing the blade directly, especially when it remains attached to the mower. Reel mowers can injure your hands severely if the blades spin while your fingers are between them. Work carefully.
Step 2: Sharpening the Blades
You can successfully sharpen reel mower blades with a blade sharpening kit, knife sharpening kit, power drill with attachments, or a sheet of metal sandpaper. It’s easiest to sharpen with power tools rather than hand tools.
Using your chosen method, observe the angle of the blade and sharpen it accordingly. Reel mowers tend to have squared blades with sharp corners that operate similarly to a pair of scissors as the reel turns. Keep this shape intact by sharpening at the correct angle on the blade edge.
Precision is important. Sharpen each part of the blade equally. If you’re using a power drill with a sharpening or polishing attachment, move the drill at a steady pace down the entire edge of the blade.
Work on one blade at a time. When you finish one blade, move to the next. Adjust your securing mechanism as you work.
Over sharpening the blades can ruin your reel and make it ineffective. Carefully sharpening only until you get the blades to the right sharpness. Check regularly while you’re sharpening to avoid grinding away too much of the blade.
Apply oil to the blades for corrosion prevention.
Step 3: Reconnecting the Mower
Work in reverse of how you disassembled it. If your reel is removable, replace it back into the mower and secure it. Reattach the reel cover, wheels, and any other parts you may have removed.
Test blade sharpness with a piece of paper or grass. Spin the blade to cut it and look for an even, smooth slice.
Maintain your reel mower regularly to keep it in top shape over its lifetime. Back lap the blade as part of your regular maintenance routine and sharpen the blade only as necessary. Reel mower blades don’t need to be sharpened as often as conventional mower blades.
Do you have questions about how to sharpen a reel mower? Let us know in the comments below.