Finish mower blade sharpening? Jigs, freehand, angle grinder, bench grinder, stone, paper?

[GBJeffOH]

Is there a consensus on the best way to sharpen finish and brush mower blades? I have an angle grinder, Dremel tool, bench grinder an oscillating edge sander. And I'm on the market to find a deal on a used 72" belt grinder. If I had the belt grinder I probably wouldn't be asking the question.

The bench grinder leaves a concave surface, the angle grinder requires some free hand consistency skills that I don't have and I'm guessing the Dremel's too small and would get to hot if removing a lot of metal. I'm thinking maybe a jig for the angle grinder?

Any recommendations?

This works real good. Not for brush hog.

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

 

[TheOldHokie]

I'm much lazier than all of you. But I suspect this is secretly a religious thread with no correct answer.

I do mine on the bench grinder. Probably once a month. After two years I'm close to putting new ones on. I've never balanced them, and they seem OK. The deck doesn't vibrate, they seemed to balance reasonably level when I did check them once.

The other things I do to my deck will do far more damage than slightly out of balance blades. And I don't think the angle is all that important - I can tell I'm slowly creeping the angle over time and I don't really mind. They still cut the grass.

Same here except I have used angle grinders more than the bench grinder. If they are nicked so bad sharpening threatens balance they get tossed. A set of 3 new blades for my RCK60 is a whopping $65 - I consider it annual Spring maintenance.

Dan

 

[chim]

Angle grinder,coarse flap disc. Grind toward the cutting edge (top side of blade), then a very light touch on the bottom of the blade in the other direction to trim off the wire edge.

 

[RCW]

Yep, I’m pretty much angle grinder with flap disc also.

Use bench grinder if beat up, but will typically change first. Don’t spend much time trying to fix a bad one.

 

[D2Cat]

4" angle grinder with a wire brush to clean, 4" grinder with a flap disc to sharpen. Balance before installing and rotate positions on deck.

 

[Sean2202]

Check out this belt grinder from Trick-tools.com. An inexpensive way to get a belt grinder that is pretty versatile. The belts are super easy to change. I have used the course grit belts to sharpen rotary blades resting the blades on the top and tilting them backwards. The premium belts hold up the best. There are also scotch-brite and polishing belts available. On mine I added the side miter table. There are also a variety of other models to choose from. I adapted mine to an old Sears 1/2 HP bench grinder.

https://www.trick-tools.com/Multitool_2_x_36_inch_Belt_Grinder_Attachment_MT362_305

 

[TheOldHokie]

Check out this belt grinder from Trick-tools.com. An inexpensive way to get a belt grinder that is pretty versatile. The belts are super easy to change. I have used the course grit belts to sharpen rotary blades resting the blades on the top and tilting them backwards. The premium belts hold up the best. There are also scotch-brite and polishing belts available. On mine I added the side miter table. There are also a variety of other models to choose from. I adapted mine to an old Sears 1/2 HP bench grinder.

https://www.trick-tools.com/Multitool_2_x_36_inch_Belt_Grinder_Attachment_MT362_305

View attachment 113492

I have that exact Crsftsman grinder. Mine is almost 50 years old...

Dan

 

[Trimley]

I sharpen mine on a CNC Water-Cooled Sharpening Table, after two sharpening sessions of an Angle Grinder. 1" Makita Belt Sander and Hand Files.

I buy 3 sets at a time for better savings.

 

[The Evil Twin]

I use stone from the 2nd tablet of the Ten Commandments with a little Unicorn blood to wet it down. The high concentration of glitter in the blood acts as a fine grit to create a spectacular edge.
I know it sounds crazy. But not as crazy as some of you guys

 

[MAArcher]

Make fun, but sharper blades (everything bladed, not just finish mowers) means better performance, longer equipment life, less breakdowns and less maintenance.

 

[The Evil Twin]

Make fun, but sharper blades (everything bladed, not just finish mowers) means better performance, longer equipment life, less breakdowns and less maintenance.

True, but we are takling mower blades here. They should be "table knife" sharp, not Ginsu blade sharp. Too sharp on a mower blade and the edge will roll.

 

[SDT]

Is there a consensus on the best way to sharpen finish and brush mower blades? I have an angle grinder, Dremel tool, bench grinder an oscillating edge sander. And I'm on the market to find a deal on a used 72" belt grinder. If I had the belt grinder I probably wouldn't be asking the question.

The bench grinder leaves a concave surface, the angle grinder requires some free hand consistency skills that I don't have and I'm guessing the Dremel's too small and would get to hot if removing a lot of metal. I'm thinking maybe a jig for the angle grinder?

Any recommendations?

No consensus.

I use a 4.5" angle grinder for both.

Flap wheel on finish mower blades in vise. Grinding wheel on all rough cut mowers on mower.

No issues.

 

[MAArcher]

True, but we are takling mower blades here. They should be "table knife" sharp, not Ginsu blade sharp. Too sharp on a mower blade and the edge will roll.

I like them at least sharp enough to chop Dwight Yoakam's head in half.

 

[Ktrim]

I have one of these. Works great.

 

[NorthwoodsLife]

Make fun, but sharper blades (everything bladed, not just finish mowers) means better performance, longer equipment life, less breakdowns and less maintenance.

You want to cut brush with a brutal and shocking whack. That means dull. That, my OTT friend, destroys stalk fibers well below the cut line.

As for finish mowers, I have a few Finns in the family by marriage, and they are sharp 1/2 the time. Dull 1/2 the time. But very opinionated.

 

[DaveFromMi]

I use a 4" angle grinder for the finish mowers. I have a 34" DR brush cutter and a 60" LandPride rotary cutter. I have never sharpened the blades on the brush cutters. I probably have 150 hrs of operation on each.

 

[leveraddict]

Unless you run over rocks and roots with your finish mower all you will ever need is a Bastard file!

 

[MAArcher]

Unless you run over rocks and roots with your finish mower all you will ever need is a Bastard file!

I'm still learning the ropes with the new-to-me tractor and 3pt finish mower. Unfortunately I've discovered a few rocks I don't quite clear and I do tend to be a little lazy and try and mulch some of the smaller branches that the trees like to litter around. I'm hoping the blades won't be in too bad a condition, but I'm preparing for the worst. I also have a brush mower that needs maintaining as well. I do like to use files on occasion though, that's how I keep the chainsaws sharp.

I've been wanting a belt grinder/sander for a while now and just haven't been able to find a deal on a 2"x72" machine. I have a little Harbor Freight 1x30 but the motor is pitifully weak, pretty useless. but I did just decide to take a change on this sander from Grizzly, should be much stronger than the Harbor Fright sander and variable speed should cover a wide range of scenarios. I have a bunch of high quality belts already so that's what made me grab a deal on this:

Variable-Speed 1" x 30" Belt/ 6" Disc Sander - Grizzly Industrial

<h1>G0864 Variable-Speed 1" x 30" Belt/ 6" Disc Sander</h1> <h2>Dial in the optimum speed for all your small sanding jobs.</h2> <p>The G0864 Variable Speed Combination Benchtop Sander offers a 1" wide by 30" long sanding belt and a 6" disc within a very small footprint.</p> <p>For a full range...

www.grizzly.com

Should help me keep the kitchen knives sharp too since no matter how much I beg for her to use a cutting board, my wife seems to enjoy hacking things up directly on the tile counter tops immediately after I spend a half day hand sharpening them with diamond stones. Sandpaper and a leather strop belt is so much quicker.

 

[mikester]

Unless you run over rocks and roots with your finish mower all you will ever need is a Bastard file!

Sandy soil here. I have to replace my blades every year because they get sand blasted paper thin.

Bring your file, I like to watch work in action!

 

[lugbolt]

people overthink this

I've been in the business for a very long time, and I've owned many, many different kinds...rotary mowers, sickles, and flails. I like flails...

Anyway, I have never once found that angle of sharpening has any noticeable difference. None. Zero. They don't last any longer with a sharper angle, nor to they wear out any faster in my experience. They don't cut any better either. They DO however, mulch a lot better and use less fuel, if you have a mulching kit-with SHARP (razor) blades. Cuts/re-cuts the blades of grass a few more times with razor sharp blades. The downside? Hit a stick, even a small one, it dings the blade tip. Dirt wears the tips down faster. Leaves do as well. Pine needles are terrible on them. And worst of all, sand or sandy soil. I have a customer at the home shop that I have to put blades on his mower every 15-20 hours of use because he drops the height adjuster into the dirt and "mows" (tills?) sandy soil in the river bottoms. Can't tell him no different either. Won't listen. But I respect him regardless of what he decides.

Hand grinder with a flap wheel, try to match the angle that was already there as close as you can. If they're really worn and the corners are rounded off, and the wings are starting to get thin or split at the ends, just replace em. Guy I referred to, runs his til the wings fly completely off and the mower starts vibrating terrible. Had one of the wings hurt his truck window, he said he found it laying next to the truck. If I have to do some bigger and thicker blades that are really worn, I will dig out the wildcat grinder. Makes quick work. With a 4 1/2" grinder it can take 45 min to an hour to get em decent on big thick blades. The wildcat does it in under 30 min but you have to be really careful with it. It's heavy, powerful, and will eat through a blade in no time.