Rear Finish Mower Finish Mower - sharpening your blades

[duffer]

Happy Memorial Day everyone, and especially all those who served, and those that gave their all for us. :flagday:

Have a 3 blade finish mower (PTO). I mow 10 acres about every other week or so, depending on rainfall.

Would like to hear from you finish mower guys how often you sharpen your blades, and the process you use. I've looked on YouTube and everybody does it differently.
Do you sharpen the front of the blade and remove burrs on the back? Front side only, back side only, etc?

I seem to be sharpening mine a lot, which makes me think I may not be using the correct process to sharpen them.

Thanx!

 

[RalphVa]

Once ran a Scag zero turn that had 3 blades. Used the same process as I use on my walkbehind lawn mower blades: Sharpen the intended side with the deep bevel, counting the # of times I run the grinder wheel down each bevel and do the same # on each side of the blade. Then turn it over and do the back side lightly, mainly to remove high spots.

If blades end up with some deep nicks, grind down perpendicular to the blade and then do your normal sharpening. This is what I often have to do on my bush hog blades. Of course, I never really "sharpen" them.

Ralph

 

[Summerlin]

Angle grinder with a low grit flap disc. Once you get the blade edge back to where you like it, sharpen often with a high grit flap disc to maintain the edge.

More frequent higher grit sharpenings will surprisingly help your blades last longer.

 

[RjCorazza]

I also use an angle grinder with flap disc. Generally 60 grit to maintain an otherwise good blade. I get the 30 degree edge, then run the flap disc lightly down the backside to debur.
I recently bought a jig that I strap my angle grinder into. I was surprised how far off my angle was after a few dozen sharpenings without a jig. The jig wasn't cheap ($149), but I'm really glad I spent the money on it... It's a mom and pop operation called Yellow Hornet. This jig will only work with flat blades, not the wavey mulching style.
Anyway, I mow about 25 acres per week, and sharpen the blades every 2 weeks or so.

 

[Smokeydog]

Multitool belt grinder. Fast without burning. Be sure to blunt the cutting edge about 1/32” after sharping. Blades will stay sharper longer without a knife edge.
Switched to Oregon G5 blades from originals helped on Woods RD7200.

 

[WranglerX]

I mow about 3 acres 3-5 times in spring with JD L120 (three blades - 48 inch deck) and sharpen by eye and try to balance them at leas once each mow season...... About ten minutes into mow after sharpening them I find a rock.... So long sharp blade.....

Dale

 

[Summerlin]

I’ll second the Oregon G5 blades. Hold an edge much longer and the lift is decently stronger than stock blades

 

[Thomas]

I also use an angle grinder with flap disc about every 4th mowing I touch the blades if I don't nick rocks or road side sand etc.

 

[mikester]

I sharpen my blades when they need it and scrape the deck whenever the mower starts leaving streaks or uncut tufts while driving at full speed. I have sandy soil so the blades get sandblasted paper thin every 1-2 seasons. If I dont hit any hidden land mines like rocks or branches then I find the blades hold their edges for a good while. Keeping the deck clean and avoiding wet grass goes a long way.

I take the blades off the mower and sharpen them to a razor sharp edge using a 80 grit flap disk on an angle grinder.

The gator blades work well and lasted twice as long as the standard high lift blades. Ive switched back to the high lifts because the leave less clumps and are better for clearing leaves in the fall.

 

[PA hayseed]

No one uses a benchtop grinder? Is this because you are sharpening them on the mower?

Anyway, since Oregon products were mentioned here, they have a web page for sharpening: Lawn Mower Blade Sharpening How-To Guide | Oregon Products

I cut 9 acres quite often, I sharpen when the grass isn't getting cut correctly (uneven/highpoints). I first tend to notice this when turning, when it starts regularly happening when going straight it is time to sharpen. I hate sharpening, because I take the blades off and they can be a bear to remove, plus I have to get out multiple wrenches and blocking. I also tend to inspect the bolts, lube them after hitting them with a wire brush, and the build up on my blades gets cleaned off (plus wd-40 or fluid film). I also scrape down my deck. I also pressure wash my deck at least 2 times a season. I didn't pay 3k for a mower deck to see it trashed. I do about the same thing with my zero turn. Since I use both pieces of equipment (7' RFM and zero turn, it spreads the abuse across the two implements).

 

[PA hayseed]

Anyone use those Orgeon blades on a zero turn? I'm interested, but don't want to waste money. The deck on a zero turn has baffles to lift grass.

 

[Smokeydog]

Woods RD7200 has baffles too. 20 years, about 30 blades and going strong.
Multitool is a bench type belt grinder. Maintaining the tip geometry when resharpening requires removing considerable material. That’s where a belt grinder shines.
We maintain rough ground that grows rocks, roots and brush. 1/2 mile gravel driveway thru the woods to mulch leaves. Got to go sharpen and lube now.

 

[John0829]

I used a bench grinder, then angle grinder for years until I discovered the joy of using a belt sander. Never looked back since, I keep a spare set or two of blades for the mowers and change when needed and sharpen when it is raining or I just need to kill some time. You can but are less likely to overheat the cutting edge using the sander, I am talking about a bench belt sander not a hand held.

 

[k0ua]

i bench ground for years. I discovered the angle grinder with flap disc and never looked back. I will never bench grind a mower blade again.

 

[Industrial Toys]

I think you see what you are doing with a flap disk and grinder. With a bench grinder. you do some, then turn it over and look what you did.

Still curious if very sharp is better over just barely sharp. Teh minutes in and the razor edge will be gone.

 

[John0829]

Still curious if very sharp is better over just barely sharp. Teh minutes in and the razor edge will be gone.

Good question, I noticed on the 1025R, 7 Iron deck when I first got it the blades had almost a 1/16 rounded edge and were not "sharp" at all and it leaves a cut second to none. However I still tend to put a razor edge on, hard to break old habits even though the OEM blades went all season without the needing touch up or sharpening.

 

[Industrial Toys]

Some say not having a razor edge from the OEM is just for liability. I can show you a nice scar on my thumb where a wrench slipped off as a kid tightening a razor sharp blade.

 

[WranglerX]

Have to say the Oregon blades for my JD L120 last about twice as long a same JD blade.... Oregon is best quality blade I have found so far...

Dale

 

[John0829]

Some say not having a razor edge from the OEM is just for liability. I can show you a nice scar on my thumb where a wrench slipped off as a kid tightening a razor sharp blade.

Yep, I have the matching scar. Sure made me change to way I tightened to blades after that.

Have to say the Oregon blades for my JD L120 last about twice as long a same JD blade.... Oregon is best quality blade I have found so far...

Dale

My experience has been just the reverse with the JD blades retaining the edge and cutting better than the Oregon blades and I have been a fan of Oregon blades for a LONG time. Sadly just not on the 1025R.

 

[Smokeydog]

Have not tried all different Oregon blades. The G5 Oregon blades have performed better than the high lift Woods blades. Stay sharper longer. Have wore out several sets of both. Set of Oregon blades cost about half of OEM.