? on how to sharpen a push lawn mower blades

T

Tar18

Joined
Oct 3, 2012
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144
Hi folks.
I was asked to sharpen a push lawn mower blades. I have never sharpened one of these so any help would be great.
So folks any ideas or help would be appreciated.
Regards
Tar ;)
 
Probably a file would be most useful, just follow the angle as closely as possible. The platen against which the blades press the grass stems can be adjusted. This adjustment is quite critical, thinking back to when I was sentenced to mow ours and the neighbors' lawns as a boy -- I think the grass had steel wool mixed in with it, or maybe that was because I procrastinated until the grass was almost too high to mow. Try adjusting the platen first; a sheet of paper should just be able to slide between it and the mower blades. That may be all you have to do. Happy blisters!
 
If you still have the owner's manual or can get one online, start there. I linked to one below, but am not sure what brand you have. Some have no direct contact between the blades and the bed knife - I do not know how to maintain those...

Normally one has to pull the wheel hub covers, spin the pawls, and swap the smaller gears side to side. This sets it up to run backward. If you have a drill with a 1/2" collet, you can pull the hub covers, pawls, and smaller gears entirely, brace the reel, and run it with a drill, otherwise, set it up and turn by hand or pull it to make the blades run backward.

Apply a smear of lapping compound to all the blades, adjust for good contact with the bed knife, and run backward till they're sharp. It might also be possible to back off the bed knife and tape some coarse sandpaper to it, but I've never done it that way. The lapping compound will break down very fine as it goes, leaving a fairly rough but geometrically clean edge. A finer finish can be made by mixing a bit of oil with finer compounds, but 220 is considered pretty fine for this sort of thing. It may require several applications...

Wash it all off when you're done - lapping compounds made specifically for reel mowers are often waterbased as these are mostly used on golf courses. Reverse the gears and you're done.

Tune the cutting bar and see if you can get a sheet of newsprint to slice all the way across each blade pass. I find I sometimes have to smack the blades with a piece of wood and hammer in some spots along the edge to get solid contact - probably the result of cutting twigs and such. The better you can get it, the lighter you can set the bar and the easier it will go.

I used to mow an entire acre with mine - get it set and keep it sharp and it goes faster than a gas push mower and easier unless the mower is powered (but then it takes longer!).

https://www.reelin.com/Manuals/204,303,304, 404 Owner's Manual.pdf
 
I use a file to re establish the edge, remove any "dings". I then use some old Lansky diamond hones to finish the edge to a very sharp edge. Works well for me. Make sure to check the balance of the blade while sharpening. I use a nail in the side of my work bench but also have one of those plastic "cone" balances as well that seems to work just as well.
 
I guess I should have asked for more clarification, I imagined a reel mower.

Regular lawnmower blades - per the above I use a single cut file to regrind the edge, and then just use a smaller file in a drawing application to refine it. Balancing with a nail works great, sometimes I just hold it up on a screwdriver shaft.
 
Balancing is important. Make sure you balance it somehow. I used to get "sentenced" to do all the sharpening at our family's hardware store. And people would bring in lawn mower blades that were sharper on the back end! We had a dedicated grinder for mower blades. If you use grinder.....keep the blade cool....just like a knife.

Best way to finish one off for me was a file as mentioned above. Waste of time to try and take it to stones. Put some bite into the edge with a file....all that is needed.

HeavyHanded.....I was thinking the same thing.....reel mower. My grandfather had one that he mounted a 4 stroke to. He also made some sort of jig to sharpen those curved blades with. I was too young to remember what he used, and he's gone now. Mower is still in the family, tho!
 
Thanks folks for all of the suggestions. It is the mower with the curved blades that you push. I have not seen it yet and I will follow the above. I will get some lapping compound and see if we can get the blades sharp or at least maybe a bit sharper than they are now.
Thanks again.
Regards
Tar :)
 
Tar18 said:
Thanks folks for all of the suggestions. It is the mower with the curved blades that you push. I have not seen it yet and I will follow the above. I will get some lapping compound and see if we can get the blades sharp or at least maybe a bit sharper than they are now.
Thanks again.
Regards
Tar :)
Click to expand...

One or two last thoughts -If its real beat up it can take a while to get it sharp again, and will be a little messy. It pays to tune the blades before sharpening if they're really out of whack because poor contact along the entire length will negatively effect how long it takes to get it sharp. I have not seen a tutorial on it, but I basically attempt to set the bed knife and see where it touches. Then I mark the places with weak or no contact using a Sharpie and give them a whack from the back side with a hammer and block of hardwood.

If its close, the lapping compound can grind enough away that you won't need the rough stuff. A lot of times the bed knife is warped as well and can benefit from a few stout whacks (take it out of the mower first). In my experience, the ones sold by Great States, Scotts, Craftsman, etc are all made in the same plant and can be a reel (couldn't help myself...) bear to tune up, especially if they haven't been used much - sharpening is the easy part.
 
Thank you heavyhanded.
I will give this a good try but as I said above, I have not seen this machine so no idea what kind of shape it is.
I will pay attention to what you said to do and hope for the best.
I will let you all know how it goes. I should be seeing it over the weekend or the beginning of next week.
Thanks again
Regards
Tar
 
Hi folks an update.
I talked to the folks about their push mower and they have decided to not do anything with the mower but bought a new powered one.
Thanks again for all of the suggestions and I will remember them if asked to sharpen this type again.
Thanks again.
Regards
Tar :)
 
If they're willing to part with it, wouldn't be a bad thing to have for resale, and to know how to sharpen one. I sold my 16" one at a garage sale to a young girl who started a "Green" lawn mowing service on her street. Worked out well for her. Several people on my street use them, as some of the yards are on the small end.

Inspired by this thread, I tuned up my 20" model and have been using it on the back yard - the front yard still gets gas powered trim because it cuts a little more uniform. I annoys me to no end having to buy gas to mow my yard, in fact it annoys me to even mow my yard! Might be time for nature's lawn mower and get a goat or two...
 
I have a neighbor up the street that has one, they look pretty nice! I'll be using my Great States one till it croaks probably as I'm too cheap to buy another. It would be nice to have something on the front that can deal with taller weeds. Often wondered if a transmission couldn't be rigged up to on-demand power a hedge trimmer type assembly, then come back and hit the lower stuff. Also could be run with brushes instead of cutter reel to toss leaves into a collection bag.

A lot of low hanging fruit with this tool if folks could stomach the higher price tag.
 
I don't know if I will end up with a push mower or not. I am needing to mow a bank that is about five feet tall. But it varies between a 30 and 45 degree angle. I just don't know about going up and down it. I only go up and down on the ends. Then across but it can't be any worse than wrestling with a true push 60ish pound gas mower across that slope.
 
My reel mower came into its own for two reasons:

My twins were just over a year old and taking two naps a day. The gas mower was waking them up and miserable when I mowed during the day, the reel mower got the job done quietly.

Second, my yard was close to an acre and I was too cheap to buy a riding mower - I'd already burned out one gasoline push mower, and realized the reel mower worked faster when pushed harder than a gas mower. I could shave close to 30 minutes off a mow and no gasoline.

I'm not sure about your slope issue, but definitely a consideration when the gas mower's weight becomes a handicap, the reel mower can become a much better option.
 
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