Sharpening Lawn Mower Blades

It depends on what you have? You could get one of those 1" belt grinders from HF. Run the blade length wise along the upper wheel.
 
I use a Rockwell belt grinder. The blades are soft, and the angle is not too fussy. My neighbor installed his blade upside down (cutting with the back non-edge of the blade), and he didn't even notice.
 
Bo T said:
It depends on what you have? You could get one of those 1" belt grinders from HF. Run the blade length wise along the upper wheel.
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I've got files, a bench grinder, an angle grinder and a 4" x 36" belt sander.
 
Use whatever you're comfortable with and don't be too fussy. You're dealing with soft, low-grade steel that won't hold an edge, anyway*. Do check to see if the blade is balanced before re-installing it, though (just hang it from a nail in the shop wall or something). If it's really out-of-whack, it will put more stress on the motor.

*A couple years ago renowned bladesmith Kevin Cashen was talking about welding hardened D2 inserts into his mower blades so they would hold an edge and give him a cleaner cut. That's a bit further than most of us would take it :D
 
www.magna-matic.comI use a Mag-9000 Magna-Matic.

Then again, I own/operate a lawn service. I used to use an angle grinder with a disk, get better/consistent results with the mag 9000
 
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coop1957 said:
I cut 40 yards a week and I rotate with 3 different sets of blades. Us a 4.5 angle grinder with a disc that is not very aggresive. Grass blade are chisel ground. Don't make the angle different than stock.
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This is how I sharpen my mower blades too. Only thing I would add is I really like this type of grinding wheel as they work excellent for this type of grinding:

flap-disc.jpg


I will note that I also don't change the angle and only remove enough steel from the blade to bring back the edge.
 
A belt sander works well also.
I cut an angled groove in a block of wood that holds the blade so the grind is level (I can easily hold the belt sander level and its comfortable).
The coarser the belt the quicker it will sharpen it without heating it up to much.
 
Brad9660 said:
There is really no point in putting a fine razor edge on a lawnmower blade, after the first lawn it will be pretty dull, plus it increases the the chance of chipping.
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Depends on what kind of lawnmower you have. :D

IMG_4350_zps24238373.jpg
 
I use a bench grinder.

I just dip the blade in water to keep it from getting too hot.

Also, I balance the blades before I put them back on the mower.

best

mqqn
 
james terrio said:
*A couple years ago renowned bladesmith Kevin Cashen was talking about welding hardened D2 inserts into his mower blades so they would hold an edge and give him a cleaner cut. That's a bit further than most of us would take it :D
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I would be at least interested in what the additional cost would be over regular blades. Not D2, but maybe 3V or S7. Something super tough to resist chipping. About 3/4 of the way through last season, I had some uneven cutting due to chips from small twigs I suppose. If I could go a whole season without messing with the blades and have a clean cut, it might be worth it.
 
I used my worksharp freehand this weekend to sharpen my blade. Worked very nicely. The Worksharp is a handy tool to have around.
 
Bastard file, angle grinder, don't forget your gloves and eye protection.
 
nccole said:
I would be at least interested in what the additional cost would be over regular blades. Not D2, but maybe 3V or S7. Something super tough to resist chipping. About 3/4 of the way through last season, I had some uneven cutting due to chips from small twigs I suppose. If I could go a whole season without messing with the blades and have a clean cut, it might be worth it.
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It's certainly viable. I'm not a welder, but I suspect that would be the only tricky part (welding in the inserts). 3V or S7 at 58Rc would be pretty dang durable, especially with such a steep bevel and if you could avoid rocks and whatnot. Full blades made of hardened steel would be pretty costly, and not real safe.

My lawn always looks like it was "mowed" by a pack of angry goats, and I'm pretty much OK with that. But for someone with a really nice lawn, or a pro, it might be worthwhile.
 
Quick question... do you need to remove the burr if you sharpen w/ a belt sander? I don't see the need personally as it will self-remove after the first 10ft of cutting. What do you guys think?
 
You pretty much nailed it there R-E-K. Chasing a burr would be a lesson in futility and waste of time. Ideally grind down to just before a burr, as a lawnmower blade does not need a real sharp edge to cut effectively. If it is too sharp or acute, it won't stay sharp very long. Look at a new one at your local hardware store and see how sharp they are from the MFG.

Blessings,

Omar
 
i sharpened some a few years ago for a friend and i used my angle grinder. since no vise was available i found that a mower blade will fit in the reece hitch on my truck which holds it at the right angle so the edge is flat. i just sat on a bucket and went at it until i had it sharp.

i would be afraid to weld harder metal to a mower blade. if the weld breaks, you will have a sharp piece of metal flying out from under the mower and going who knows where. you could get a set carbidized :D (i might suggest that to daniel fairly and see if he will give it a try :D)
 
i use a magnematic 8000 i own my own buis cutting and landscaping,they are pricey but faster and really no better than my $15 angle grinder from harbor freight.
 
THE PUNISHER said:
i use a magnematic 8000 i own my own buis cutting and landscaping,they are pricey but faster and really no better than my $15 angle grinder from harbor freight.
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I was looking at the Magnematics... what to they suggest as far as: 1. removing the burr and 2. not overheating the blade.

It seems to me as if the blades probably aren't HT'd and tempered so that way they will be lower hardness in case they hit something hard. Does anyone know if this is true or not?
 
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