How to Sharpen a Reel Mower

by Darren Bush on June 28, 2013 · 24 comments

in Manly Skills, Outdoors, Projects

mower

It’s 1968. I’m sitting on the front step of my grandfather’s little house in San Diego. Gramps is pushing a reel mower across his front yard, wearing a Pendleton shirt and a pair of khakis. I hear the snickety-snickety-snickety of the blades. I smell cut grass. He lets me carry the grass catcher and dump it in the trash (this is pre-compost era).

Drive around on a Sunday morning nowadays and in the place of church bells, you’ll hear a chorus of lawnmowers. Gas-guzzling, air-polluting lawnmowers. A gas-powered mower spews more pollution than eleven cars and is responsible for 5% of the greenhouse gases produced in the U.S. Just as bad, homeowners spill more than 17 million gallons of gas a year topping off their lawn and garden equipment. That’s more than the Exxon Valdez.

Reel mowers are also better for your lawn. Instead of rotating blades that chew up and whack off the top of the grass, the reel mower’s blades act like a pair of scissors that snips off the top. Check out the difference between a rotary mower’s cut on a blade of grass vs. a newly-sharpened reel mower:

bad-vs-good-blade

On the left; surgical precision from the reel mower. On the right, well, not so much. A clean cut heals faster and reduces the chances of disease. No kidding.

I believe there are several reasons for the rise of power mowers. Just as the average house has doubled in size since the 1950s, so have lawns. Mowing a giant lawn with a 18-inch reel mower is probably out of reach for many people, or at least we think it is. Pushing a reel mower is a nice workout, but we are a sedentary society. The idea of pushing a reel mower is puzzling to people. It takes longer. We don’t have time, or at least we believe we don’t have time. Brett has done some work on this topic already and outlined for us the benefits of using a reel mower — and he owns and uses one himself.

I believe smaller lawns and larger flower beds and gardens are a good thing. Then, reel mowers make a lot of sense. They’re smaller, easier to store, quiet, require very little maintenance, and have a genteel aesthetic sitting in your garage or garden shed.

Recycling an Old Mower

If you’re looking to buy a new reel mower, Brett’s guide here is quite handy. But another option is to recycle an old reel mower by giving it a tune up. The good news is that old mowers are usually built like Sherman tanks. Quality steel blades retain their strength; all the mower needs is a good cleaning and honing.

mower-done

Above is Exhibit A: a Craftsman Reel Mower, about 40 years old. I bought it from an old guy who had it at a garage sale. It hasn’t been used in at least 15 years, but the parts were sound and he was willing to let it go for $25. He wanted $35 but there weren’t many takers. I took it home and stuck it in my garage to acclimatize to its new home.

A few days ago I pulled out the Craftsman 18, hosed it off to get the cobwebs and dirt off, and started the sharpening process. Today, I’ll walk you through how it’s done whether you’re restoring an old gem or maintaining one you’ve had awhile.

How to Sharpen a Reel Mower

There are two critical parts of a mower: the blades and the bed knife. The rest of the mower exists to support these two parts. Wheels drive a gear that spin the blade mechanism, which consists of a series of 5 to 7 blades mounted in a helical fashion. The angle helps snip the grass better. A roller behind the bed knife allows you to adjust the height of the cut.

hosed-off-2

Now it’s tempting to pull out the files, angle grinders, and just start grinding and filing. Not only is this not necessary, it has the ability to ruin the mower. You need a tight clearance to cut. Filing blades and bed knifes is like trying to sharpen scissors in the same manner. No bueno. Since reel lawn mower blades work like scissors; they’re not necessarily as sharp as they are exact. The edge of the blade needs to be true and close to the bed knife. That’s what lapping does.

lapping-kit

To lap your blades you need two things; lapping compound, an abrasive, and a way to turn your blades. A lapping kit consists of a container of lapping compound and a crank. The lapping compound is basically a heavy duty abrasive, but suspended in a thicker goo so it doesn’t come flying off the blades when you spin then. The handle fits the shaft of most mowers…except in my case, which is fine, as I had other ideas. You’ll see.

remove-drive-wheel

So let’s lap! Start by removing the drive wheel, which is usually the left one when you’re standing behind the mower facing forward. Remove whatever covers the attaching mechanism. Sometimes it’s a nut, sometimes a cotter pin, and in my case, a retaining ring. Whatever it is, remove the wheel and you’ll see the gear that drives the blades.

remove-cog

Remove the gear as well, removing whatever is retaining it. Now you will see the shaft that drives the blades.

You want to adjust your blades so that they are in contact with the bed knife. This is done several different ways on different mowers. Usually it’s some sort of combination of a threaded rod and a bolt, although some use a screw and a retaining bolt. Whatever it is, adjust the blade so that it contacts the bed knife equally across the whole width of the blade. Note: if a blade is bent badly so that it hangs up on the bed knife when the others spin freely, a few taps with a hammer or a twist with a pair of pliers can restore the blade, but avoid it if possible. Most of the time the engine (you) can’t generate enough power to bend the blades while moving, so they’re usually straight.

If you spin your blades now, there should be a little resistance and a scraping noise. That’s good. It means the blades are a little too close to the bed knife. Time to change that.

apply-compound

Using a small brush, paint lapping compound on the blade edges. You don’t need much, just a bead across each of the blade edges.

Once coated, start cranking…but do it backwards. That’s right, you want to knives to sharpen backwards. The lapping compound between the bed knife and blades does its job as the blades run so the cutting edges never meet.

Crank for a long time. Ten minutes, maybe. Re-apply lapping compound. Crank some more. You’ll start to see a flat, shiny surface on the blades where the compound has abraded away the surface and created a precise edge matched to the knife bed. Add more compound, keep cranking. At this point (below) you can see the start of a shiny edge, even though there’s still some corrosion showing. That’s okay.

start-to-see-change

Your arm will probably start to hurt. Reconsider your cranking abilities. I did, and rigged up a cordless drill with a little jury-rigged socket and a piece of inner tube. Whatever works. Making sure the drill was on low and running backwards, I started slow and ran the blades for a minute, added more compound, and ran the blades for a little longer and a little faster. You’ll hear a difference as the lapping progresses; the scraping sound lessens as the blades are honed and material removed.

close-up-adapter

I think I ran the drill for a total of five minutes, adding compound just a few times. Once I saw a shiny finish along each blade, I was done.

sharp-edge

Clean off the compound as best you can, and examine your blades. If there are any spots that look like they’re not quite as clean as other surfaces, you can add more compound and adjust the bed knife so it is closer to the blades. Don’t worry, you’re not going to run out of blade. My mower didn’t need a second lap.

I then backed the blade off just a tiny, tiny bit. You want the gap between the bed knife and the blade to be less than a piece of grass or it won’t cut anything. I’m talking very small back-off, maybe a few thousands of an inch.

testing-sharpness

Test your lapping job with a piece of paper. It should cut like scissors. If it doesn’t, adjust the knife bed until it does.

replacing-cog

Now reassemble your mower in reverse order, cleaning up as you go and re-greasing anything that needs it.

If you’re restoring an old mower, after sharpening the blades you can spruce it up further if you want a fun little project. Chrome polish, steel wool, and a little gun oil on the blades, and a good old toothbrush with some Simple Green can clean it up real nice. Paint the fenders and bars if you want to. Replace the grips on top. Use motocross hand grips if you want to be bad-ass.

sweet-cuts

Adjust the roller in the back to its highest setting. Push it across some nice green grass, listening for the snickety-snickety that was so familiar to Gramps. A Pendelton shirt and khakis might just complete the picture.

{ 24 comments… read them below or add one }

1 Eric June 28, 2013 at 9:17 pm

On mine, if you swap the wheels the reel turns backwards. So you look like an idiot pushing it back and forth on your sidewalk, but it’s way easier than cranking.

2 Bob June 29, 2013 at 2:45 pm

I am using a Mclane 17 inch 7 blade reel mower. I have the lap kit for it and will refrence your piece at the end of the mowing season. Thank-you. The Mclane push reel is professional grade. The frame is the same one used for their powered models, there is even an option battery powered model. The cost is not much more than the Fiskars but well worth it. The ultimate powered reel with a storied history is the Locke CL powered reel mower. Their you tube video also shows how to sharpen and Lap the blades a basic task with all reel mowers. If your yard size requires a Locke you have arrived. For the man that wants to know how a reel mower really works, Toro has an excellent an excellent pdf “Fundamentals of Reel Mowers.” The Brill web site has only entry level consumer grade reel mowers, Mclane will never be listed theres they are not available at your local box type retailers. For the frugal man that appreciates quality tools consider the McClane, the “straight edge razor” of reel mowers. Are there any other Mclane fans?

3 minuteman June 29, 2013 at 3:50 pm

I bought a reel mower and a “Lee Valley” honing kit. sharpened that thing to within an inch of its life and had it set up perfectly. I still couldn’t cut my lawn with it. It probably would have worked great on a golf green, but on my not perfect lawn it tended to push the grass over in a way that the grass was never actually presented to the blades properly. I ended up selling it and buying an electric lawn mower.

4 Blair June 30, 2013 at 1:49 am

(Sorry, girl encroaching on man’s area!)
I recently graduated from college, moved into a little home and decided to get a reel mower. Like “minuteman”, I have a lot of trouble cutting the lawn with it, as it simply pushes some of the grass over without cutting it. I probably looked like a fool going over my front yard 3+ times in a row yesterday.

Any advice?

5 austinrks June 30, 2013 at 8:17 am

The reel mower is perfect if you have thin grass. I’ve used one growing up and remember it fondly. Now I am finally in my own house and the first thing I bought was a reel mower for myself. Turns out not all grass is compatible, this thick stuff in Texas just laughs at the reel mower. I ended up mowing over 3 times and there were still areas that were not getting cut down. I sadly had to trade in for a small gas mower. You will love the reel mower if your grass isn’t too thick.

6 The Western World June 30, 2013 at 9:03 pm

This is a great article. I think the reel mower is a great way to cut the grass and stay fit. Thanks for posting the info and helping to keep alive the disappearing art of repairing things. I’ve saved this article for when Im ready to sharpen my mower!

7 MarylandBill July 1, 2013 at 11:08 am

@austinrks,

Most types of grass can be cut with reel mowers, but not all mowers will cut every type of grass. The thick lawns of many southern grasses need a 6 blade reel, but most reel lawn mowers have 5 blade reels. If you want to give it another try, you will find plenty of info online. One benefit of those southern grasses with the right reel mower is you can cut the grass to look like a Golf fairway.

8 William July 2, 2013 at 12:12 pm

So makes a good, high quality reel mower? My wife and I have taken to using a scythe around the house. It’s nice, but takes way too long, and I’ve been looking for something that would combine the clean operation of the scythe with greater speed.

9 BOB July 2, 2013 at 1:50 pm

William:
Read my post regarding Mclane reel mowers. It will last a lifetime. A scythe, really? It’s possible I suppose. I recall the scythe in “Cool Hand Luke.” When your wife takes a break does she say, “Just checking my YO-YO boss.” Once the road gang got into the “swing” they got a great cut.

10 William July 2, 2013 at 2:44 pm

Bob,
Yes, a scythe. It actually works very well. Just very slow.

11 Bob July 2, 2013 at 6:00 pm

I am impressed. I am a booster of the Mclane mower but to be honest a less expensive mower may suffice. I talked with the head gardener at the International Peace Gardens in ND. He mows his home lawn with a reel mower, “What Brand?”. I was going to brag my mower up, he didn’t know his brand and didn’t care. Now this is important :
1. He mows his lawn up and down, back and forth and up down. This during the same mow. He gets a perfect cut.
2. His lawn gets little foot traffic so he mows it high about four inches..His lawn stays green while shortcut neighbor lawns brownout during dry spells.
3. When the grass begins growing in the spring he gradually raises his blade height to the desired level, a little higher with each mow.. This is less stressful to the grass.
3. He keeps it sharp.
Enjoy your lawn. Croquet anyone?

12 Will July 7, 2013 at 5:34 am

My first house had a very small yard (the total lot was 50 X 100. Take away the house, the back deck, etc, and you get very little grass). So I bought a reel mower, because I loved the sound, and the fact that it didn’t burn gas, etc. Plus it was old-school, like me.

The problem was when the grass grew just a little too long. Like others who have commented, the mower would just push the tall grass down, rather than cutting it. I sadly gave up and bought a power mower.

Now I’ve got 3/4 acre, and there’s no way I could cut that with a reel mower.

13 Farseer July 8, 2013 at 3:33 pm

I picked up the Fiskars Staysharp Max suggested by Brett in a previous post, and I’ve really loved using it on my lawn. Two years ago, I completely killed and replanted my yard, and my gas mower didn’t seem to treat it very well. Going with the push-reel instead turned out to be a great choice, though there has been a learning curve:

1.) Tall grass pushes over, and does not cut well. Tall grass that doesn’t get cut keeps getting pushed over while growing longer – it’s a vicious cycle. I found the only way to avoid this is to stay on it and mow more often when the grass is growing quickly. Twice a week at the minimum. You may even have to raise the blade pretty high for one pass and then come back the next day at your preferred height. It didn’t take me long to figure out my mowing frequency, but once a week in the spring totally didn’t work.
2.) Cut at different directions each mowing. I actually have three directions that I cycle – 2 diagonals and straight across. This helps keep the grass from pushing down as much.
3.) Hardwood mulch is a bear. When it spills out or is flung out of a flowerbed by my trimmer, it has the potential to stop the mower. Every couple of mows I rake along my beds to help keep this to a minimum. This also helps raise up some of the grass that may have gotten a bit longer near the beds so I have a better chance to cut it with the mower.
4.) You need to keep an eye on the blades, especially if you hit chunks of hardwood mulch from time to time. If it seems like the mower is missing blades that it should be cutting, take a couple of minutes to get the blades to the right height.

I have a nice, thick tall fescue blend in Kansas, and after I worked out these few things, I’ve never been more proud of my lawn. I took some shots of my landscaping recently (http://imgur.com/a/sFnfs#0), and you can see the lawn a bit in a few of them. This was actually right before a mow, though, so it’s not as pretty as it could be. :)

14 Farseer July 8, 2013 at 4:37 pm

Never mind, I do have some pictures of the yard from this spring: http://imgur.com/a/ZMIz9

15 Eric July 12, 2013 at 12:00 pm

So I just picked up an 18″ Yard-Man “silent” reel mower and the manual claims it should only bend the paper, not actually cut it. It doesn’t give any sharpening instructions (just says to bring it in to a shop). Should I ignore that and follow the instructions here anyway?

Thanks, and great article!

16 R.A. Stewart July 16, 2013 at 2:17 pm

Excellent tutorial, thanks! I have the compound and crank and the counsel of our neighborhood hardware guy, but this gives me the visuals and step-by-step guidance I need. (We will draw a discreet veil of silence over how long I have had the compound and crank.)

“I took it home and stuck it in my garage to acclimatize to its new home.”

I like this. I have a number of tools and gadgets in this situation, and I will try thinking of it in this more kindly way.

17 John B. July 29, 2013 at 10:09 am

What did you do to adjust the socket and rubber tube to fit over and grip the drive shaft. I have a craftsman and some high grit valve grinding compound that I want to use up versus buying a kit for a handle that I may not need. I have been unable to get the drill and socket to effectively grip. Your help would be appreciated.

18 John G. September 11, 2013 at 1:18 pm

If you’re having a problem with the mower “pushing over the grass” most likely you have not adjusted correctly the “knife bed” or “cutter bar” that the reel cuts against. Google it or read the manual with the mower for proper adjustment of the cutter bar. OR maybe your grass is just WAY too high. Reels don’t do well on very tall grass or on weedy uneven turf.

19 Swamp Yankee Bob September 21, 2013 at 9:07 am

With over an acre of lawn I needed a riding mower, (old guy who likes old school), but wanted a reel mower…Ta Daa…found a 1963 National with a 3 HP Clinton motor. It sips gas, mows great, and is a “reel” eye-catcher..

20 Suzanne March 22, 2014 at 10:48 am

What a fantastic article and tutorial. Exactly what I was looking for – I’d adopted a reel mower from neighbours who were moving and were THROWING IT OUT (I know, right??!!) and tried it late last autumn on the lawn. Beautiful machine but needs some TLC. Now that spring is almost upon us I shall give it the care and attention it needs and get it back up to scratch. Thank you!

21 Travis April 4, 2014 at 5:08 pm

Does anybody have a preference or recommendation for the brand of compound to use, what grit and better yet, where to buy it?

22 Dale E. Claus April 11, 2014 at 7:00 am

I had a problem cutting my bentgrass with my McLane 10-Blade Reel mower when the grass was wet or a little too tall, the rear wheels which prower the blades would skid. So, I powered up my Mclane 10-Blade Reel Mower using a Razor Scooter 24 Volt motor, about 5 hours work in the shop to install, but not brain surgery, ha! I can cut my 5,500 sq. ft. bentgrass lawn twice before charging the batteries. I sharpen the blades use the back lapping method with 200 grit, then 400 grit… be sure to wipe off all of the grit before using the mower. First you must make sure that the bedknife is perfectly straight, this may require taking the mower apart. dclaus@columbus.rr.com

23 Dale E. Claus April 11, 2014 at 7:15 am

Buy lapping compound on ebay, under $30 for a pint is a bargain. Don’t use anything less than 220 grit on your reel mower blades on the first pass. One seller now has this: Clover Compound Silicon Carbide compound 400 grit 16 oz. can, he is selling several grits.

24 J Hays April 15, 2014 at 10:19 pm

I have the same mower that the young lad in the top picture is leaning on, I am looking for the bottom roller as mine is wood and finally rotted out, can you tell me where to find one? Thanks.

Respectfully: J Hays

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