Keep Those Blades Sharp!! No need for expensive sharpeners!!

[577jersey]

I have a couple of questions.

1. I've never balanced my blades, relying on removing similar amounts of metal from each end. I've never noticed any vibration from the deck due to imbalance. Would I notice it if there was any?

2. I notice the OP grinds the blade almost all the way back to the hub. Most blades I've seen are sharpened only for about the outer 4" or so. It's the tips that do most of the cutting. Half way back to the hub the blade speed is only half the tip speed and doesn't cut much anyway. Also, it's the tips of the blades that get to the grass first and farther in the the grass the blade sees is already cut.

3. Okay, one more question. You can see it in the video, the tip corners of the blade take the most abuse. If I were to sharpen the blade straight each time I'd have to remove a lot of metal each time, which would take a lot of grinding and the blades wouldn't last long before there was nothing left. So atbthe tips the sharpened edge starts to take on an angle or a rounded profile that likely does not cut as well. What do you all do?

Its not rocket science bro..just follow the factory edge and balance them once in a while..I have blades that are sharpened all the way back to the lift bend and they still cut ok.
You wont notice much vibration if any until the spindle bearings start to go bad.

 

[oldyellr]

Its not rocket science bro..just follow the factory edge and balance them once in a while..I have blades that are sharpened all the way back to the lift bend and they still cut ok.
You wont notice much vibration if any until the spindle bearings start to go bad.

Oh, I don't doubt blades sharpened all the way to the hub cut okay, it's just that I don't think anything but the outer 4" or so do any cutting. Yes, I follow the existing bevel when sharpening, but the angle will drift off during the life of the blade.

 

[577jersey]

Oh, I don't doubt blades sharpened all the way to the hub cut okay, it's just that I don't think anything but the outer 4" or so do any cutting. Yes, I follow the existing bevel when sharpening, but the angle will drift off during the life of the blade.

Yes ,,I know what you mean about the rounded angle after many sharpenings sir.I was following the factory edge across the blade in the video,it was a Bobcat 16" off set blade.
It may effect the cutting ability slightly but not more than losing the factory 30 degree cutting angle.Once a blade edge gets halfway back to the lift bend i consider buying a new set.

Using the 40 grit flap wheel does not remove much material at all,,i noticed if i touch up my blades once a week they only take 5 light swipes or so to get the edge again and last all week.
I cut on AVG about 15-20 hours a week per machine on a set.I like my blades to have a nice edge,just seems to leave less scraglers.

I am no pro,,just the way I have been doing it for years now and it seems to work well.

Tom

 

[bertsmobile1]

1) vibrations are funny things. There is a whole dicipline withing engineering to deal with vibrations.
Some that toss you out of the seat will do no damage while others that you can not feel over the engine will break the mower in 1/2.

2) Each end every blade has a specific length of sharp edge.
Some are even sharpened on both sides while others are just sharp for the last few inches.
So you don't change the length .

3) The theory has it you keep the line from the corner to the end of the grind a strait line.
Only people with a blade grinding machine ever seem to do it as it is too much work.
When the corner gets too round you will start to leave mowhawk lines between the blades so it is time for a change.

 

[Carscw]

I have never sharpened a blade half way back to the wings.
I get about 6 weeks out of a set of blades. The wings get so thin they start breaking off.
The only people that say a blade needs to be perfectly balanced is the ones that sell a blade balancer.

 

[oldyellr]

Yes ,,I know what you mean about the rounded angle after many sharpenings sir.I was following the factory edge across the blade in the video,it was a Bobcat 16" off set blade.
It may effect the cutting ability slightly but not more than losing the factory 30 degree cutting angle.Once a blade edge gets halfway back to the lift bend i consider buying a new set.

Using the 40 grit flap wheel does not remove much material at all,,i noticed if i touch up my blades once a week they only take 5 light swipes or so to get the edge again and last all week.
I cut on AVG about 15-20 hours a week per machine on a set.I like my blades to have a nice edge,just seems to leave less scraglers.

I am no pro,,just the way I have been doing it for years now and it seems to work well.

Tom

Yes, I don't believe in grinding away a lot of blade until the leading edge corner is again square, so I let it be rounded or angled, but still put an edge on it. Sure, it won't cut as well as a 90 degree corner. I just use whatever cut-off wheel I have on my angle grinder, so it cuts faster than your flap wheel. However, it takes me about an hour to cut my lawn each week and I have 2 mowers I alternate in opposite directions, one with a mulch plate, so I only sharpen the blades once a year unless I hit a rock or something.

 

[oldyellr]

3) The theory has it you keep the line from the corner to the end of the grind a strait line.
Only people with a blade grinding machine ever seem to do it as it is too much work.
When the corner gets too round you will start to leave mowhawk lines between the blades so it is time for a change.

Yes, that's the theory. In practice you would have to grind away a lot of blade whenever the leading corner gets rounded, but I just put an edge on the rounded part and make sure both ends are similar for balance. Back before I was retired and had access to the maintenance shop at work, I thought of making a jig for the surface grinder to sharpen my blades. It would take the same amount off each end and leave a square corner. That never happened.

 

[Maxrevs]

Here is a quick video on how I sharpen blades...hope it may help somebody save $$ down the road!!

Thanks for a great tip, Tom.

I've tried your method and I find it's:
- much faster than using a bench grinder
- it's much easier to maintain the factory angle due to better visibility
- removes much less material
- generates much less heat so there's no need to quench
- produces a lovely flat & even finish.

I use it all the time now and I really appreciate the tip.

That's the great thing about this forum, people sharing their knowledge and experience willingly for the benefit of others. Thanks to you all.

 

[577jersey]

Thanks for a great tip, Tom.

I've tried your method and I find it's:
- much faster than using a bench grinder
- it's much easier to maintain the factory angle due to better visibility
- removes much less material
- generates much less heat so there's no need to quench
- produces a lovely flat & even finish.

I use it all the time now and I really appreciate the tip.

That's the great thing about this forum, people sharing their knowledge and experience willingly for the benefit of others. Thanks to you all.

Your very welcome brother,,this method wont work for everybody but I find it has served me very well over the years,,you will get better at it after some more practice.

Tom

 

[577jersey]

I have never sharpened a blade half way back to the wings.
I get about 6 weeks out of a set of blades. The wings get so thin they start breaking off.
The only people that say a blade needs to be perfectly balanced is the ones that sell a blade balancer.

I ran blades for a couple seasons and never had wings get so thin they break off..must be the sand down there,,up here we have alot of clay and good top soil.