How many working hours before you sharpen lawn cutting blades?

ctfjr

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Doesn't matter what you use, a ZT, push mower or the tractor with a finish cutter, how long before you sharpen the blades? Assuming you haven't hit something other than grass.
Also how do you sharpen yours?
 

Henro

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May 24, 2019
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I just use my guilty feeling to tell me to buy new blades.

I never sharpen them...not worth it to me.

Guess I measure blade changes in conscience terms rather than performance. I have short weeds that look like grass, rather than grass.

LOL but really honestly true after 20 years plus all told.

I don't even envy those that have real grass...must be a western PA red neck thing...not a red neck though...maybe a closet red neck without realizing it? Have to think about this further...LOL
 
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WoodKutter

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Kinda like asking how long until you sharpen your chainsaw. It depends. If the wood or grass is clean, you don't hit dirt, you can cut quit awhile if it's sharp. It takes very little dirt or rock and it's time to touch it up.
 
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Mowbizz

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Bx25d
Aug 19, 2021
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When I had my BX 60” deck I would sharpen at the beginning of the season. Now that I have a Kubota zero turn I will sharpen them mid season. ( already sharpened and balanced them before the first mow.)
I bought an All American sharpening system and it is the balls. That and an Oregon balancer mounted on the garage wall and it’s like a pro mower shop! 😊
Also bought a Mo-jack pro lift to make it all easier yet.
 
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Biker1mike

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B6200, Kubota 2030 Front Blade, King Cutter 60" finishing deck
Jan 11, 2022
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Beginning of the season I pull the deck up to 90 degrees and check out the blades. If they look decent I do not bother, if they are beat up I'll have them sharpened.
 

pjoh784350

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BX23, quick attach bucket, 3 point, pallet forks
May 3, 2019
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If a green, healthy lawn is important to you then keep an eye on the grass tips. Dulling blades tear the grass tips and that tear browns quickly while the rest of the blade stays green. Almost causes your lawn to look like it beginning to burn despite adequate water. The frayed tips can also promote disease. So it all depends on how much you cherish a green lawn to dictate how often to sharpen. Lawn services sharpen daily (or at least should).
 
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JimmyJazz

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B2601
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This is a good question. I bought my new B2601 About 1 year ago and just took the mowing deck off for the first time in conjunction with performing the 50 hour service. The bottom had crud built up as expected and the blades were quite dull. I attempted to sharpen them a bit with an angle grinder without removing them. I give my effort a D- . The deck seems to cut the same as when I first got it and both before and after my feeble effort. I am not a lawn keeping professional so take it for what its worth. My yard looks as good cut wise as the neighbors who employ professionals.
 
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Captain13

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M7040 4WD ROPS, ZD28, Woods (84” box blade, 72” harrow, 48” pallet forks)
Feb 27, 2019
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Kathleen, GA
I do mine on the ZT and the RFM twice a season. I use the Woods method using a flap disk. Smooth the top wedge and then square the cutting edge off (instead of sharpening the cutting edge) to a width of about 1/16 inches. The blades stay sharp longer and require less metal to be removed during the sharpening process. And yes, the flat cutting edge cuts smooth.


According to Woods, this makes the blade less likely to chip and makes for a stronger blade.

‘’when I check the blades, if they are in pretty good shape already, I just face off the cutting edge with the flap disk without having to remove the blades. Takes about 10 minutes to do that.
 
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Mark_BX25D

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Bx25D
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... keep an eye on the grass tips. Dulling blades tear the grass tips and that tear browns quickly while the rest of the blade stays green. Almost causes your lawn to look like it beginning to burn despite adequate water.
(y) This is the best way to tell.

There are too many variables to give a number.
 

ctfjr

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Thanks for all the input!
pjoh784350 hit it. I noticed that I have some areas where the cut tips look dead. I'm thinking that the blades have dulled up even though I probably have <30hrs of use on them.
I cut 4" high so pretty much no chance of hitting the ground. Certainly no sign of that on the lawn.
Just seemed like a short time to need sharpening. It may all be a moot point as I currently debating between a rfm or zt - if I can find one :)
 

RCW

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Late to the party, but each spring needed or not.

Usually use a bench grinder.

Used an angle grinder with a 60 grit flap disc last couple years.
 
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lugbolt

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ZG127S-54
Oct 15, 2015
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depends

is your gras thick or is it thin?
is your grass coarser or is it all weeds or ??
Do you mow when it's really dusty?
Do you mow in sandy areas?
Do you mow when it's damp/wet?
Do you mulch (with dedicated mulching kit)?

Rotary mowers have one of the worst possible environments to live. Blade life is subjective to all of the environments that they are used in. Thus, it's always wise to make you first few mowing cycles and then check your blades. If the tips are rounded down (not square) and/or your cutting edge is worn, you know about what kind of maintenance you'll have to look at

On mine, I mulch, using standard Kubota mulching blades. The blades last me 2 seasons (Mar-Nov including the dry leaves and pine needles in later Nov). I generally check them every mowing but usually don't have to even touch them up. And mulching, they don't stay sharp as long nor do they last as long, also they are VERY sensitive to rocks/dirt/dust. Oh, almost forgot, the cut quality will absolutely suffer if the blades are not perfectly sharp when mulching. I also have to clean the bottom side of the deck more often than when I was side-discharging.
 

SDT

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multiple and various
Apr 15, 2018
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Doesn't matter what you use, a ZT, push mower or the tractor with a finish cutter, how long before you sharpen the blades? Assuming you haven't hit something other than grass.
Also how do you sharpen yours?
I sharpen lawn mower cutting blades once each year in the fall during annual maintenance.

For years I used a file for lawn mower blades, both walk behind triming mower and 5' ahd 6' MMM decks for Kubota CUTs. I would go through at least one file each season so last year I decided to use flap disc on 4.5" angle grinder. A good 14" file now costs about $15 and HF flap discs cost less than half that and last multiple years.

Unlike most (all?) I dress my rough-cut mower blades after each use with a 4.5" angle grinder. I use my rough-cut mowers (5', 6', 15') as HD finish mowers and almost never hit anything with any of them aside from grass and the occasional stick or branch. Sharp blades cut better and use a bit less fuel.

I find it easier and less time consuming to dress the blades after each use rather than performing heavy grinding once or twice each year.

Simply raise mower, reach under from behind with angle grinder and dress blades. Takes about 10 minutes for single spindle mowers and about 30 minutes for BW, which is used only 2 or 3 times each year. Technique is a bit different for BW but still quite simple.

Yes, I go through rough-cut mower blades faster than anyone else due to the routine grinding.

No, I do not cut saplings with sharp blades. I keep a spare set of dull blades for the 6' cutter for the rare occasions when I need to cut saplings. Haven't used them for over 10 years but keep blade pins well anti seized so changing blades is not difficult.

SDT
 
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imnukensc

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BX2380
Sep 10, 2015
396
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Midlands of SC
Newly sharpened blades go on in spring. Old ones taken off and sharpened and put back on next spring. And also have another set of spare blades. I use a bench grinder.
 

Mark_BX25D

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Bx25D
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Virginia
pjoh784350 hit it. I noticed that I have some areas where the cut tips look dead.
How much of the tip? Ther'es always going to be some die back after it's cut, even with sharp blades. What you want to look for is how shredded the tips are.
 

mikester

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M59 TLB
Oct 21, 2017
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www.divergentstuff.ca
I have sandy soil and my blades get blasted paper thin at the end of a season. If I don't hit any surprises I can go a couple of months on a sharpen for my ZTR. I take the blades off and sharpen them at the same angle as OEM to a knife edge using a 5" flap disc 80 grit on my grinder.

If you keep your deck clean and scraped you will find it cuts better even with dull blades. I scrape the bottom of my deck when I do my regular greasing service when I refill the diesel tanks every 12 hours or so.

I use my old RFM for bush hogging, I only sharpen those once a season if required. Grass buildup under the RFM deck isn't an issue because I don't cut at 17kph.
 
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GeoHorn

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Rotary Cutter (shredder) blades = never.
Lawn Mower = at start of season

Both Woods and Rhino recommend leaving a 1/8” flat edge on shredder blades. Tractor Mike has a video with a blade supplier…who recommends… Never. (and it’s his job to sell you blades.)
 
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Snark

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L245, rotavator, scrape blade, rotary log splitter, boom pole.
Feb 27, 2022
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eastern NC
A full mowing session takes me 3.5-4 hours. Right now with heat and drought I might do 70% to not overstress. I resharpen every 3-4 sessions using a side grinder and file. I'll try the flat edge method and compare.
 
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chim

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L4240HSTC with FEL, Ford 1210
Jan 19, 2013
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Near Lancaster, PA, USA
No set time. I do watch for brown tips as mentioned. I use a 20V DeWalt cordless grinder with a flap disc to dress them. I sometimes even check them on a cheapie balancer even though the flap disc doesn't remove much metal.

I use a slightly curved edge (top only / flat on bottom) as opposed to a flat grind on the top. Can't say if it makes any difference, but the deck has been cutting really nice.