Mower blade care

L

Lt.Col.Vortex

Joined
Jul 22, 2012
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752
Mt brothers and I are in charge of yard maintenance for some mortgage companies, and on average we get about 80 calls a month. So keep mower blades sharp and in shape is a must. Up until now I've used a 4" grinder to sharpen my blades, but I think I'm doing more harm than good. Should I be treating these blades like knives?? The grinder heats up the edge up quite a but and I think in the re-heating process it blade is loosing its temper. Should I be using some other sharpening method other than a grinder?? Or should I just take more time and not let the blade get as hot?

The blade has a number on it and I don't know if its a steel type or just a part number. The number is 3403.
 
All you need is a working edge on a mower blade. The grinder should be just fine. Even if you convexed them to have a slightly stronger edge, you will hit things that will destroy that anyways.
 
I sharpen mine with a big file, been doing it that way for decades. :)
 
mower blades dont need to be very sharp in the first place since they usually get destroyed anyway.. If you have a thin/sharp edge its going to get ripped to shreds more so than if you have a thicker/blunter style edge.. I honestly dont even think they are heat treated either because of the fact that they would break so easily when you hit something..

I've always sharpened mower blades with a good file, and use a grinder to blend in damaged spots.
I really wouldnt worry about it much if what you're doing is working for you.
 
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One summer I played with convexing my mower blades. It gave a pretty cut, but not only will sticks and stones break your bones, they play hobb with your blade edge. This is one area where good enough is good enough. I do try not to burn the edge when sharpening.
 
I have sharpened the lawnmowers at work and none of them would hold an edge long. After putting a keen knife edge on the 'prop' for the riding mower the groundskeeper would cut the 2 or 3 acres of lawn around the building and afterwards the edge would be gone, and before long it would be round and blunt. The best I could do was to put a steep angle to reduce the wear. I think part of the problem comes from the abrasive effects of dust and sand that acts like a sandblaster as it sucks up and mulches the cuttings, and that the steel is very soft to prevent the prop from shattering into shrapnel should the operator hit a rock or the curb.
 
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I have a spare mower blade for both my push mower and tractor, both are Snappers...my push mower is 20 years old and still starts by the second pull :)...I have always used a hand file and vise to sharpen my blades. I have done it this way because I've never had a bench grinder hehehe but over time I find I prefer this method. I can control the process and the edge I want without over heating the blade.
By having an extra blade it is easier to just swap out the dull for the sharp blade and sharpen the dull blade when you have the spare time. I give the spare/sharpened blade a thin coating of grease...Park bicycle lube that I've had for years...to prevent rust.
 
I ride a Scag ZTR mower and I cut quite a few acres a month. And I'm going as fast as i can on these properties so I can get to the next job. Its understandable that the blades wear down fast, I was just looking for ways to better extend the life of the blade. The grass cut season last 6 months for me, and in that time I cut on average 500 acres. I'm running three blades on this mower, and after 6 months those blades aren't worth spitting at. Its coming close to the end of the season and the blades are wearing down rather fast. Its not a problem yet, its just a pain because I have to sharpen every 2 weeks.

I tried the steeper angle theory, but in reality there is not combating the abuse these things face. I was just concerned that while sharpening I was removing the temper. But since I'm fairly convinced that these blades didn't have a temper to begin with, I'll just continue to complain every time I have to stop work to sharpen blades :) :)
 
I use a small hand grinder and don't even take the blade off. I do frequent touch ups since it is fast and easy. All I work for is a working edge and I kept the original chisel grind my had all along.
 
I work in the golf maintenance industry way down south and have many rotary bladed machines in my fleet cutting all year round. Best setup for me is whatever is quickest. I have a Foley rotary blade sharpening grinder but I typically just use a 7" angle grinder with a metal cutting stone and mount the blades in a vice. I aim for an even 30 degree bevel while watching for excessive discoloration. Limit the downward pressure, let the grinder do the work. If it heats up too much, do the other side for a while. Do not sharpen to a razor sharp edge, but do sharpen to an even edge. The BALANCED WEIGHT of the blade in rotary blades is what is most important, so obtain a blade balancing device if you don't already have one. Take metal off each side at 30 degrees until the blade is balanced. Have a spare set for every machine and keep the tuned ones in stock for quick replacement.

Here in an example of a blade balancer:

http://www.baileysonline.com/itemde...=41050471825&gclid=CKD-89q7g7ICFcqe7QodBEQAdA

It mounts on a wall and bearings inside allow gravity to let the blade spin freely. The heavier side of the blade is indicated by the side closest to the ground when it comes to a stop.

By the way, there IS a temper on the blades. If there wasn't it would be destroyed the first time you used it. Blades are essentially truck leaf springs with a hole and two edges.
 
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Every time I sharpen, I rotate the blades ( because one side wears down faster then the other ). But I never thought about balancing..I'll look at that.
 
Arakiel is on target, I was just in university for a degree in Landscape design and installation and a 4 in grinder and balancer are standard practice.
 
Vortex, I am glad you see value in my information. From an engineering perspective, consider the probable damage to the spindle bearings and housing due to excessive vibration from an unbalanced blade. Balancing your blades will also visually improve your quality of cut. In my profession, after-cut appearance is almost everything.
 
Arakiel said:
I work in the golf maintenance industry way down south and have many rotary bladed machines in my fleet cutting all year round. Best setup for me is whatever is quickest. I have a Foley rotary blade sharpening grinder but I typically just use a 7" angle grinder with a metal cutting stone and mount the blades in a vice. I aim for an even 30 degree bevel while watching for excessive discoloration. Limit the downward pressure, let the grinder do the work. If it heats up too much, do the other side for a while. Do not sharpen to a razor sharp edge, but do sharpen to an even edge. The BALANCED WEIGHT of the blade in rotary blades is what is most important, so obtain a blade balancing device if you don't already have one. Take metal off each side at 30 degrees until the blade is balanced. Have a spare set for every machine and keep the tuned ones in stock for quick replacement.

Here in an example of a blade balancer:

http://www.baileysonline.com/itemde...=41050471825&gclid=CKD-89q7g7ICFcqe7QodBEQAdA

It mounts on a wall and bearings inside allow gravity to let the blade spin freely. The heavier side of the blade is indicated by the side closest to the ground when it comes to a stop.

By the way, there IS a temper on the blades. If there wasn't it would be destroyed the first time you used it. Blades are essentially truck leaf springs with a hole and two edges.
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Thanks for typing all of this. I guess were both golf course mechanics :) Could you imagine trying to explain how to grind reels and bed knives on here, much less set them!

To the O.P. I can't beleive you go six months without sharpening. That is a really long time. Once a week is pretty standard, and I've even seen once a day (which I think is excessive).
 
Great advice and suggestions. I've always balanced my mower blades...bad things can and do happen to the mower when the blades are out of balance.
 
If this equipment was mine I would get a blade balance, but the guy who used it before me tore the hell out of the stuff. 80% of the bearings where seized and the deck would not move ( raise or lower ). I've given about 10 more years to this mower in the 5 months I've had it..it was in pretty bad shape.

Now dont get me wrong, I take better care of things that dont belong to me than my own equipment. But the $10,000 of yard equipment I got from the boss I wouldn't pat $10 for, that how bad it was. So I dont really care to much about propper blade weight at this point. Ther is a million more important problems to consider first.

me and my brother are on a 6 month job trial, and once the allotted time is up will have a choice to make...whether or not to carry on with this line of work. And if we decide to keep on we're going to dump close to $20,000 in brand new equipment, custom trailer and a whole bunch of goodies. Thats when I'll go all out and buy specialty tools for everything.
 
Look me up when you do. I'd be happy to provide any professional advice you might need.
 
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