I got a new mower and was fixing to sharpen my blades.. My dad has always just free handed it using a bench grinder.. I have seen tools to help sharpen the blades more evenly, are these tools worth it or is free handing it just as good??
sharpening mower blades
- Thread starter S Chamblee
- Start date
I use a bench grinder or a hand held grinder and a vise. Be sure to keep it pretty well balanced by taking the same amount off of both ends.
I have used MANY techniques to sharpen mower blades (bench grinder, hand file, gimicky gadgets.....etc) A sharp blade needs less power to cleanly slice the turf. This results in measurable fuel savings.
the typical blade does not "wear out".... it is sharpened so many times that there is not enough metal left to be safe. Hence, you want to remove as little metal as possible when sharpening.
Short of having a special $500 blade-sharpener for home use I have found that a handheld angle-grinder with a FLAPDISK may be the best way to sharpen blades. Just clamp the blade to a sawhorse and touch it up with flapdisk
This is because a flapdisk tends to follow the existing contours of the blade and maintain the existing angles. Also, a flap-disk is easier to control the amount of removed material.
the typical blade does not "wear out".... it is sharpened so many times that there is not enough metal left to be safe. Hence, you want to remove as little metal as possible when sharpening.
Short of having a special $500 blade-sharpener for home use I have found that a handheld angle-grinder with a FLAPDISK may be the best way to sharpen blades. Just clamp the blade to a sawhorse and touch it up with flapdisk
This is because a flapdisk tends to follow the existing contours of the blade and maintain the existing angles. Also, a flap-disk is easier to control the amount of removed material.
If you've got a dinged up blade a flap grinder won't work too well. Hand held grinder with vise. Balance it on a finger from the center point. Touch it up with a file if you want, it's just grass. Putting greens are a different story.
I chock the tractor, raise the mower up high as it will go then use a bumper jack (hard to find now) to pick up the rear a little higher....then block it up and slide under on a blanket with eye and ear protection and polish them up with a 4" grinder. Been working good for a long time (on my old rig) and expect the same on the new one.
They DO wear out. At the very tip of the blade, the outer tip of the cutting edge, it wears with use, and rounds over. When it's rounded, it'll affect cut quality. It happens because the effective cutting circle of the blade becomes smaller in diameter which reduces blade cutting path overlap, so if you have 3 blades, you'll begin to notice the mower cutting 3 paths instead of one wide path. Same thing happens as the blades are sharpened over and over, material is removed and makes the effective diameter of the blade's cutting path smaller.
The wings also wear down with use. Typically when mowing dusty areas or sandy areas, they'll wear a LOT faster. Same for mowing/mulching leaves and pine needles. They'll wear to the point where the wing gets thinner at the top/outside edge, and lots of times will wear where the bend starts. I've seen them develop a groove, sometimes crack because they get thin, sometimes the crack propogates and throws the remainder of the wing off somewhere (neighbor kid's face?). This is why it's important to keep an eye on them.
If you like a good cut quality, replace them as opposed to sharpening. Many will argue, but I have enough experience in lawn and garden (and my own landscaping company) to know that they do wear out and affect cut quality. Some customers like a fine golf-course style cut and those are the ones who will gripe if the stripes are 18" wide and uneven (on a 54" 3 blade deck). My yard is just exactly like that currently as my blades are worn. They don't look bad but they are worn and it's affecting cut quality. Time to replace them.
As far as sharpening, just use an angle grinder with the blade clamped in a vise. It doesn't make a huge difference on the angle and/or how even they are, if you look at brand new blades, they're not perfectly sharp-actually they have about a 1/32" flat edge at the face of the cutting edge which keeps them from getting dinged up and wearing so quickly. Balancing, I just use a screwdriver through the hole and put the tip of the screwdriver on the bench edge. The heaviest edge will fall obviously. I can tell no difference between doing it this way and precision balancing with a cone-style balancing jig; plus it's faster. I've also got an Oregon blade sharpener specifically made to sharpen mower blades and it does a good job, but takes forever and makes a TON of noise. I use it to touch up on newer blades that haven't been used much but really the angle grinder is faster, quieter, and does about the same thing.
The wings also wear down with use. Typically when mowing dusty areas or sandy areas, they'll wear a LOT faster. Same for mowing/mulching leaves and pine needles. They'll wear to the point where the wing gets thinner at the top/outside edge, and lots of times will wear where the bend starts. I've seen them develop a groove, sometimes crack because they get thin, sometimes the crack propogates and throws the remainder of the wing off somewhere (neighbor kid's face?). This is why it's important to keep an eye on them.
If you like a good cut quality, replace them as opposed to sharpening. Many will argue, but I have enough experience in lawn and garden (and my own landscaping company) to know that they do wear out and affect cut quality. Some customers like a fine golf-course style cut and those are the ones who will gripe if the stripes are 18" wide and uneven (on a 54" 3 blade deck). My yard is just exactly like that currently as my blades are worn. They don't look bad but they are worn and it's affecting cut quality. Time to replace them.
As far as sharpening, just use an angle grinder with the blade clamped in a vise. It doesn't make a huge difference on the angle and/or how even they are, if you look at brand new blades, they're not perfectly sharp-actually they have about a 1/32" flat edge at the face of the cutting edge which keeps them from getting dinged up and wearing so quickly. Balancing, I just use a screwdriver through the hole and put the tip of the screwdriver on the bench edge. The heaviest edge will fall obviously. I can tell no difference between doing it this way and precision balancing with a cone-style balancing jig; plus it's faster. I've also got an Oregon blade sharpener specifically made to sharpen mower blades and it does a good job, but takes forever and makes a TON of noise. I use it to touch up on newer blades that haven't been used much but really the angle grinder is faster, quieter, and does about the same thing.
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I used to use a hand held grinder if the blades were bad(chips and dents) and a flap grinder if they were still in good shape. I would finish them with a file to polish them up and remove burrs. I have since switched. I bought one of the Work Sharp knife sharpeners to use at my full time job to sharpen knives for customers. It has a rotating head and removable guard so you can sharpen axes. I tried it one day on my lawn mower blades and they turned out sharper than when I was using a grinder and file. The edge also lasted longer because of the "curve" the sharpener puts on them. The belts follow the edge and don't grind anything that isn't needed. once done, I would balance them on a nail to make sure I didn't take to much off one side or the other.
beaterboss
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L3901, LA525-FEL, BMLX-3164 3pt Blower, 72" Coteck Sno Pusher, 60" Box Blade
From my experience. Get an extra set of blades for your machine, and keep one set ready at all times. I used to sharpen mine with a 4" Angle Grinder in a Vise, polish off with a hand file, then balance with a nail driven into the wall or a bubble balancing thimble. Be sure to wire wheel and clean the blades completely before sharpening, even a little bit of crusted on grass will throw the balance off. Balance is critical on blades, especially for commercial equipment. The tip speed on finish mowers for example, in the 60" class, is much higher than your regular riding or push mower bought at Wal-Mart. Being unbalanced causes unnecessary wear on the spindles, and for walk behind mowers it can actually snap the crank shaft. (I have actually seen this happen). After sharpening, take a little of the edge off of the blade. I know it sounds counter to what you are looking for, but you don't actually want a "Knife-Edge" on your blade. Reason being that the sharpening job will last much longer and be more durable without the "Razor Blade" finish. After sharpening, paint your extra set of blades you just sharpened, or give them a good shot of WD-40, so they will be in pristine condition for the next use.