How To Sharpen Reel Mower Blades With A File Or Sharpening Compound

Reel lawn mowers are enjoying a resurgence in popularity. As a manual mower, they cut grass as you push it along.

Yet just like their rotary blade cousins, the blades on a real mower can dull, or need a basic adjustment. 

Fortunately, there are a few different ways to sharpen reel mower blades. In this article, I’ll tell you how to sharpen reel mower blades with a file or use a sharpening compound for the best possible cut performance.

How Does a Reel Lawnmower Work?

A reel lawnmower has a set of curved blades that turn in concert with the wheels. When you push it forward the blades spin and contact the grass along with a special “Cutting Bar.”

This essentially snips off each individual blade of grass. Some reel mowers are set up to then carry the cut blades into a small collection bin.

This is a nice feature, as it removed the spent blades before they can turn into thatch, which can gradually start to choke off the layers of your turf.

Thatch can be a major factor if you are cutting the grass infrequently, or your lawn is overgrown. Thatch can also build up in dry conditions where there simply isn’t enough moisture to allow it to decompose.

However, small grass clippings and tiny pieces of thatch tend to break down in wet conditions.

This can even help to feed and fertilize the upper layers of your turf in the middle of the growing season. In a situation like this, cutting your grass frequently can help feed your lawn!

Whether or not you need to use a collection bin can vary depending on the recent weather and how long your grass is.

If your reel mower doesn’t have a collection bin, and the spent grass clippings are longer than half an inch, you should strongly consider raking them up after you mow.

Yes, it’s true that a reel mower does take a little more effort to operate. It also takes a little longer to cut the same patch of grass than a conventional rotary lawnmower.

Still, when it’s properly maintained, the reel mower isn’t that much more work than say pushing a heavy gas lawnmower without a self-propulsion system.

Will Dull Blades Affect My Reel Mower?

The sharpness of the blades can affect a reel mower in a variety of ways. Since the wheels and the blades essentially work in tandem, when the blades start to dull it will make it more work to essentially push the mower along.

At the same time, dull blades are also more likely to push over blades of grass rather than cut them.

Significantly dull or rusty reel mower blades can also damage grass making your lawn more prone to turf disease, pests, and potential fungus issues.

Can I Sharpen Reel Mower Blades?

Reel mower blades are designed to last longer and stay sharper than rotary mower blades. Still, as time goes on they will inevitably start to dull, and perhaps develop pits of rust.

This is even more likely to be an issue if you frequently let your lawn grow longer than 4-inches or if you cut the grass when it’s still a little damp.

Some rotary lawnmower blades can be sharpened with a bench grinder or electric handheld power grinder. These are the wrong tools for the job when it comes to sharpening a reel mower blade.

how to sharpen a reel mower with a file?

In my opinion, a mill file is an ideal tool for sharpening reel mower blades. Some hardware stores will even carry special mill files that are specifically designed for sharpening reel mower blades.

But to be honest, a simple handheld mill file is all you need. If you’re looking for one, we recommend this grinding mill file.

Here are 5 steps you can follow to sharpen the blades on a reel mower using a file.

1. Secure the blades to prevent the reel from spinning

This calls for wedging a broom handle or a hardwood dowel into the blade assembly to keep it from accidentally turning while your fingers are in the “Danger Zone.”

Laying the mower on a large work surface and chocking the wheels with a doorstop or shims would also be a good idea.

Don’t think that just because the blades are too dull to cut grass that they can’t give you a nasty finger wound!

2. Clean Away Any Debris like grass and dirt

You can use a stiff wire brush or some coarse sandpaper to carefully remove any debris from the blades and surrounding surfaces. If you use sandpaper, make sure it is rated for metal.

3. scrape the file on the blade between

To do this you carefully press the toothed end of the metal mill file on the beveled edge of the first blade.

The goal is to angle the plane of the file to perfectly match the beveled edge of the blade. You aren’t trying to create a new angle.

You are just trying to remove a millimeter or two of dull metal to replicate the original sharp beveled edge.

This usually takes three to five passes, depending on how rusty or dull the blade edge has become.

4. Repeat previous steps 3 to 6 times

Once you have filed away as much as you can on the first blade, you will need to remove the broom handle and carefully rotate the cylinder to fully access the next blade. Then re-secure the blades and repeat the sharpening process.

5. Lubricate and Protect blades after sharpening

When you are done sharpening all the blades, you should light spray all moving parts with a penetrating lubricant like WD40.

You should also coat the blades with penetrating lubricant, or a little bit of linseed oil soaked into a clean paper towel.

Use A Sharpening Compound on Reel Mower Blades

There are some manufacturers who make a special type of sharpening kit which allows you to sharpen reel mower blades using a process known as “Back Lapping.”

It is essentially a kit that comes with a handle and a modest amount of a gritty substance called a sharpening compound.

To sharpen reel mower blades, you basically need to apply it to the blades with a chip brush, and it will gradually sharpen the beveled edges as they scrape against each other.

Then you use the handle or “Lapping Tool” to turn the reel mower’s driving gear. You move the blades in one direction for three or four passes. Then you turn the blades in the other direction.

It’s honestly a little more elbow grease than the file method and it takes longer. In my experience, it also doesn’t sharpen the blades as well.

The main benefit of this back strapping and sharpening compound method is that you don’t have to worry about matching the bevel angle of the blades.

How Can I Adjust the Blade Alignment of My Reel Mower?

Improper or maladjusted blade alignment can hinder the efficiency of your reel mower blades. This also tends to leave excess grass behind as well as accelerate the dulling process.

In fact, some people think that their blades are dull, only to find that they simply need to be adjusted.

Fortunately, with a little bit of mechanical skill, it’s pretty simple to adjust your reel mower for optimum performance. ​

First, you need to place your reel mower on a tabletop or workbench and chock its wheels from moving.

At that point, you can use your hand to slowly spin the reel to see the level of imbalance. If you hear a scraping sound, you will likely need to use a bed knife to adjust the blades.

If you notice the reel spins too easily, or it seems loose, you need to adjust the blades to be closer to the horizontal cutting bar.

When you feel that you have the blades dialed in where you want them to be, you can take a flathead screwdriver to adjust the screw slots on the side of the reel.

In general, if you need to bring the blades closer, you will tighten the screws. If the blades need to be moved away, you will need to loosen the screws.

Try to make these adjustments in small increments. After each one makes another soft, slow spin to see how much more adjustment might need to be made.

The Value Of Routine Maintenance

You shouldn’t let the fact that a reel mower is manual and seemingly simple, lull you into thinking that it doesn’t need maintenance.

Just like any tool or piece of machinery, a little bit of routine maintenance will go a long way toward making the most out of your investment. Learn more about how to sharpen blades for hedge trimmers or grass shears that you may have.

When you really put it all into perspective, sharpening the blades, making minor adjustments, and spraying a little penetrating lubricant on the moving parts is cheaper than maintaining a gas-powered lawnmower!