Sharpen Rotary Mower Blades?

[LarryBud]

I have a 5' Land Pride. My local dealer claims the blades never need to be sharpened ( at least that's one persons opinion ).

Do you all sharpen your Rotary Mower glades and if, how do you do it?

 

[Elliott in GA]

No. You are creating problems and wasting time sharpening rotary cutter blades; finish mower blades are another thing. If your blades are that beat up (missing chunks or out of balance), you are better off replacing them or having them professionally reground. FWIW, my rotary cutter blades show some damage, but they still cut grass relatively well - to my surprise. However, my finish mower cuts grass much more cleanly and evenly as you would expect.

 

[mcfarmall]

I knock the big burrs off mine periodically, maybe every 5-10 years or so.

 

[GreensvilleJay]

I used to do the mower at friend's farm, twice a season. Tilted the deck up, spend 15-20 minutes making them sharp and ding free. Also made sure they'd swivel freely and remove the 'stuff' wrapped around the spindles.....
The 12 acres of grass wasn't bad, it was 'expanding' the edges that did the damage. Little things like rocks, fence wire,saplings, etc. are what dulls/damages blades.

 

[NCL4701]

I started to replace the blades on ours after I’m not sure how many decades of intermittent use because it was so dull it would beat down 3’ broomstraw but wouldn’t really cut it so it left the front field looking like a dog with mange after a fight with a bobcat. The edges were so beaten up the were rounded into what looked like a 1/4” diameter bead where the chamfer should be. Reground a dull chamfer on them with an angle grinder and am getting some more life out of them (that was 3 years ago). Raising the lift with the toplink all the way in and chaining the deck to the ROPS (I wouldn’t sit under hydraulics only) allowed me to sit on a mechanic stool and easily regrind them. So can’t say I’ve never reground them but “sharpening” would be a stretch. That was once in about 40 years at probably 20 hours a year use.

Argument I’ve always heard for NOT sharpening: If anything you’re mowing includes saplings or other woody growth you don’t want to regrow, it’s preferable to not cut cleanly. A clean cut gives the plant the best chance of surviving and putting out new growth. A dull blade will shatter the stem leaving it ragged and much more susceptible to sap loss and disease/insect attack. The last part of the argument is, “If you want a clean cut, get a finish mower.”

In my experience there’s probably some truth in that, but if you’re cutting nothing but grass I don’t see what harm there would be in sharpening other than some time and taking some life off a grinding wheel. YMMV.

 

[SDT]

I have a 5' Land Pride. My local dealer claims the blades never need to be sharpened ( at least that's one persons opinion ).

Do you all sharpen your Rotary Mower glades and if, how do you do it?

Unlike most others, I keep the blades on all of my rough-cut mowers sharp.

I sharpen new blades before installation and dress with 4.5" angle grinder after nearly each use. Takes about 5-10 minutes for single spindle mower, about 30 minutes for BW (once each year in fall).

I mow only my own ground and never hit anything aside from the occasional grounding in dirt.

No, I do not cut saplings with sharp blades. Rather, I keep a set of old blades for my 6' cutter for saplings, which are almost never cut anymore. Don't want to cut saplings cleanly with sharp blades leaving sharp stalks to damage tires on next round.

Yes, I do replace blades more often than anyone else due to the routine grinding.

Sharp blades cut much better and use less power and fuel doing so.

 

[mcmxi]

Unlike most others, I keep the blades on all of my rough-cut mowers sharp.

I sharpen new blades before installation and dress with 4.5" angle grinder after nearly each use. Takes about 5-10 minutes for single spindle mower, about 30 minutes for BW (once each year in fall).

I mow only my own ground and never hit anything aside from the occasional grounding in dirt.

No, I do not cut saplings with sharp blades. Rather, I keep a set of old blades for my 6' cutter for saplings, which are almost never cut anymore. Don't want to cut saplings cleanly with sharp blades leaving sharp stalks to damage tires on next round.

Yes, I do replace blades more often than anyone else due to the routine grinding.

Sharp blades cut much better and use less power and fuel doinig so.

Yep! I agree 100% with this. I cut about 30 acres over the summer months at my place and a friend's place. I have two sets of blades for the rotary cutter and keep a sharp set on hand at all times.

 

[Flintknapper]

What and how you use your shredder for should be key in deciding whether to 'dress' the blades when needed (or not to).

IF a person is mainly knocking down saplings...then I agree the blades do not need attention very often.

BUT for lesser tasks (tall grass, weeds, briers, rough stemmed plants) you will do MUCH better with a blade maintained to the same profile as new from the factory.

Actually 'sharpening' a blade (making it literally sharp) defeats the purpose of a shredder blade and it will quickly dull anyway.

But maintaining the 'profile' of the edge (as new or nearly new) doesn't take that long, results in better cutting/shredding and is much easier on the tractor (especially lower hp compacts).

 

[LarryBud]

Thanks All,

I actually use my mower for everything around my 31 acre farm. I mostly mow grass and weeds but it's not unusual to grind up some brush which seems to be constantly intruding.

 

[GreensvilleJay]

To the 'camp' that never sharpens the blades, consider that the manufacturers spent a LOT of money and time sharpening the blades you buy. If it wasn't necessary, they could have saved a lot of money, labour costs, floor space,etc. and even had a higher profit margin.

As for saplings, a 'spot' application of some kind of tree killing chemical will solve that problem.

 

[Elliott in GA]

Well, probably most users do not sharpen their rotary cutter blades; and yet, they are pleased with the results. Of course, most users probably bought a rotary cutter to do what a rotary cutter was designed to do - cut down rough vegetation (big weeds, saplings, bushes and etc.). If you are just mowing grass, then sharpening your blades might make sense if you are no longer happy with the cut quality. I have a finish mower to cut grass in the field.

My blades still have a factory profile over 90%+ of their cutting surface, and I will not be correcting/sharpening them. I will undoubtably hit some more rocks. Rocks are everywhere on the property, and even at 5 inches of cutting height you will hit them occasionally - especially mowing/reclaiming rough areas.

In 5 - 8 years, there will likely be enough blade damage for me to buy/install a new set - less than $150. If I sharpened/reground my blades now (enough to remove the rock strikes), I would most likely cause more problems by weakening the blades (making the blades more brittle from the heat of grinding).

To those that suggest sharp rotary cutter blades result in less wear on your tractor and better fuel economy, I ask - by how much? You probably do not know and cannot find a number. It makes logical sense, and it is probably true. However, it is a virtual certainty that the amount of savings is insignificant. It is probably on the same order as arguing about a 1/2 PSI difference in your truck's tire inflation.

Rather than just adopting some routine for sharpening or replacing your rotary cutter blades, I would suggest waiting until you are not pleased with the cutter's performance. You can then evaluate the blades based on their condition and your usage.

 

[GBJeffOH]

I have a 5' Land Pride. My local dealer claims the blades never need to be sharpened ( at least that's one persons opinion ).

Do you all sharpen your Rotary Mower glades and if, how do you do it?

I have 12 finish mower blades to sharpen so I bought this.

All American Lawn Mower Blade Sharpener

We provide high quality lawn mower blade sharpeners at an affordable price. Our products are made in the USA and built to last. We also provide video tutorials about the best way to use our jigs to sharpen your blades.

www.allamericansharpener.com

It works great.

 

[GreensvilleJay]

re: Rather than just adopting some routine for sharpening or replacing your rotary cutter blades, I would suggest waiting until you are not pleased with the cutter's performance.

This probably should be called the 'goodenuff' method. Over years of mowing ,every cut ,while worse than the previous, is 'good enuff', and you don't see that the grass is being cut the way it was on day one....jes goodenuf.... by the time you do SEE it's bad, you need a new set of blades. Neighbour up the road is like that..when told he needed new blades( totally wore out...) he said 'can't afford them, it's goodenuf'.......

don't ask about the tires on his 3/4 ton pickup......!!!!

 

[armylifer]

I have the kubota RCK54 MMM and I sharpen the blades twice per year. I use a file to take out the small nicks and a bench grinder to take out any large nicks. I replace mower blades as necessary, whioch works out to once every couple years.

 

[PoTreeBoy]

Thanks All,

I actually use my mower for everything around my 31 acre farm. I mostly mow grass and weeds but it's not unusual to grind up some brush which seems to be constantly intruding.

I think you'll find sharp blades will mulch brush better, as well as cut grass better.

 

[Flintknapper]

I think you'll find sharp blades will mulch brush better, as well as cut grass better.

^^^^^^

Agreed.

I can't imagine a single thing that a blade with the original factory profile (level of sharpness) would not do better than a blunted blade that's been on the mower for years and years and subject to who knows what.

I can see LOTS of people being too lazy to do the periodic maintenance on them though.

And even more folks falling back on 'Well that's good enough' instead of doing a good job and taking pride in their work. I can see that.

Don't agree with it....but its a choice a lot of people make.

 

[Elliott in GA]

Oh please - now people that do not sharpen their rotary cutter blades are lazy and do not take pride in their work.

I will say it again, if you use a rotary cutter for what it was designed to do (to cut rough areas, woody plants, bushes and etc.) you do not need to keep them sharp.

If you just or mostly use your rotary cutter to cut grass and you want it to look its best, then sharpening (really just touching them up) the blades is probably worth it.

As the owner of a rotary cutter and a finish mower, I say people that try to use their rotary cutter as a finish mower are: using the wrong tool, too cheap to buy the right tool and take no pride in their work.

 

[Flintknapper]

Oh please - now people that do not sharpen their rotary cutter blades are lazy and do not take pride in their work.

Yes a good number of folks KNOW the blades need to be 'dressed' (if not replaced) and are just too lazy or cheap to do it. I stand by that. Making exceptions for some areas SO ROUGH that the blade would need constant re-dressing. Some folks deal with rocks and hardwood saplings and would spend more time dressing the blades than shredding.

I will say it again, if you use a rotary cutter for what it was designed to do (to cut rough areas, woody plants, bushes and etc.) you do not need to keep them sharp.

Well....I'd say that depends very much on your equipment and what you are cutting. I have some areas on my property that basically needs to be 'reclaimed'. Has gotten overgrown with Ragweed, Small Sweet Gum Saplings, Green-brier, Blackberry vines, Cherokee Rose, 2 ft. high Volunteer Rye. A dull rotary cutter just beats these down into a tangled mess that remains about a foot high unless you just crawl along at Box Turtle speed. Even then.... it leaves a bunch a long stemmed, matted debris behind. A sharp blade cuts and mulches it, allows for much faster travel as well.

If you just or mostly use your rotary cutter to cut grass and you want it to look its best, then sharpening (really just touching them up) the blades is probably worth it.

Yes, grass that has been reasonably maintained is no issue...if all you want to do is kinda whack it down some. But again it depends on the grass. In the spring time my pastures quickly grow into a VERY thick Volunteer Rye. If left to get over about 18" before cutting....I guarantee any tractor under 50 hp is going to feel it. Then later in the season the pasture grows into Bahia and Coastal Bermuda. Try cutting those with a dull blade. Most of it will be standing right back up the next day.

As the owner of a rotary cutter and a finish mower, I say people that try to use their rotary cutter as a finish mower are: using the wrong tool, too cheap to buy the right tool and take no pride in their work.

Agree completely. Use the right tool for the job. You'll never hear me argue that. I WILL argue however....that a rotary cutter blade kept reasonably 'sharp' will never be a bad thing and will always do a better job than one that has an edge that looks like a piece of rebar. I will also argue that a lot of people KNOW this but are just too lazy to do the maintenance. OR....they don't pride in their work.

^^^^^^

Expand for replies.

 

[NCL4701]

Interesting discussion. In a non-professional setting never really considered sharpening a knife, chainsaw, mower blade, or much of anything else just because it’s the second Tuesday in June or whatever predetermined date. Oil changes, greasing, etc. I understand. I understand the utility of such scheduled sharpening of edged tools in a production or industrial operation but I’m not running one of those at home. If something gets dull, it gets sharpened or replaced as appropriate. I suppose that’s some folks definition of lazy. OK.


This is the kind of stuff I routinely mow with our rotary cutter. Sometimes worse, sometimes not, but pretty average (except for the log which was moved shortly after the pic was taken).

This is typical of what it looks like when I’m done mowing. This is the same part of the sewer line as the first two pics above, just at somewhat different viewpoints. And yes, the lone tree by each riser is left intentionally as a marker for when the flora achieves heights greater than the sewer riser.

This is a sewer line. It’s not my yard. My primary goal in mowing it is to keep it open as an occasional thoroughfare and occasional shooting lane. It is literally “good enough” for me and everyone else who is welcome on our property. If someone requires a solid stand of weed free tall fescue trimmed to precisely 3” to carpet their path to a deer stand, I’d probably prefer they go elsewhere anyway. To some, that means I take no pride in my work.

So according to some I’m lazy and take no pride in my work because I don’t use a calendar to sharpen my rotary cutter blades and when I do “sharpen” them it’s just restoring the original profile, not a true sharpening like a finish mower blade.

Thought about that some. Maybe I should pick it up. Do better. Be better.

Nah. This actually is good enough for me. By which I mean it meets every goal I have and every requirement to maintain the sewer line and other areas I mow a couple times a year with the rotary cutter. And if it isn’t good enough for someone else… well, they probably wouldn’t want to be seen with a lazy, incompetent hack like me anyway so they’ll never be subjected to experiencing having to see or traverse my shoddily maintained property so it shouldn’t bother them either.

 

[Flintknapper]

Interesting discussion. In a non-professional setting never really considered sharpening a knife, chainsaw, mower blade, or much of anything else just because it’s the second Tuesday in June or whatever predetermined date. Oil changes, greasing, etc. I understand. I understand the utility of such scheduled sharpening of edged tools in a production or industrial operation but I’m not running one of those at home. If something gets dull, it gets sharpened or replaced as appropriate. I suppose that’s some folks definition of lazy. OK.


This is the kind of stuff I routinely mow with our rotary cutter. Sometimes worse, sometimes not, but pretty average (except for the log which was moved shortly after the pic was taken).
View attachment 92220 View attachment 92221 View attachment 92222 View attachment 92223

This is typical of what it looks like when I’m done mowing. This is the same part of the sewer line as the first two pics above, just at somewhat different viewpoints. And yes, the lone tree by each riser is left intentionally as a marker for when the flora achieves heights greater than the sewer riser.

View attachment 92224

This is a sewer line. It’s not my yard. My primary goal in mowing it is to keep it open as an occasional thoroughfare and occasional shooting lane. It is literally “good enough” for me and everyone else who is welcome on our property. If someone requires a solid stand of weed free tall fescue trimmed to precisely 3” to carpet their path to a deer stand, I’d probably prefer they go elsewhere anyway. To some, that means I take no pride in my work.

So according to some I’m lazy and take no pride in my work because I don’t use a calendar to sharpen my rotary cutter blades and when I do “sharpen” them it’s just restoring the original profile, not a true sharpening like a finish mower blade.

Thought about that some. Maybe I should pick it up. Do better. Be better.

Nah. This actually is good enough for me. By which I mean it meets every goal I have and every requirement to maintain the sewer line and other areas I mow a couple times a year with the rotary cutter. And if it isn’t good enough for someone else… well, they probably wouldn’t want to be seen with a lazy, incompetent hack like me anyway so they’ll never be subjected to experiencing having to see or traverse my shoddily maintained property so it shouldn’t bother them either.

Soft, moist vegetation there. Easily mowed with just about anything. Looks fine.

Doesn't require any Drama and Hyperbole in rebuttal. In your case I wouldn't expect to have to 'dress' your rotary blades very often....if ever.

But YOUR situation is very different than mine and that of others.

What would be of more use would be a pic of the rotary blades on your mower. I'd wager the edges are not as round as a coke bottle...right? IF it were....I expect you'd be getting very different results.

No one is suggesting you dress the blades per a calendar, but also not buying into the idea that they NEVER need to be sharpened because so and so said so on a YouTube video.

It is your privilege to do as you like on your property and use your equipment as you see fit. As for trying to do a better job (within reason), take pride in our work, or even be a better person, yes I think those are worthy goals.

But everyone was raised different and have different ideals, that is well understood and appreciated.

IMO your results look just fine (if that matters).