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

#1

5

577jersey

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

Tom



#2

R

Rivets

If it works for you great, but a couple of things I would do different. You really should clean the blade first to get a correct balance. Doesn't look good and affects balance. If you are cutting the bottom of the blade to get it razor sharp, you factory cutting angle has changed. Your razor sharp edge will last one or two cuttings, depend on conditions, and is not needed. No factory blades are that sharp or need to be. All factory blades have a .020-.040 thick edge. As I said if it works use it, but to others, you should some things to accomplish a better job.


#3

ILENGINE

ILENGINE

The world largest blade manufacturer Oregon, uses what they call the 30-30 rule. Angle is ground at 30 degrees and leaving a .030 blunt cutting edge. No need to make a razor edge, which will immediately wear off,


#4

B

bertsmobile1

Nice video.
Just one point.
If and only if you lawn is clean with no stick, stones or protruding roots should you put a sharp edge on a ride on blade.

A "razor edge" will cut better and cleaner but will dull very fast and dent badly when it strikes anything other than nice soft clean grass.


#5

5

577jersey

Rivets said:
If it works for you great, but a couple of things I would do different. You really should clean the blade first to get a correct balance. Doesn't look good and affects balance. If you are cutting the bottom of the blade to get it razor sharp, you factory cutting angle has changed. Your razor sharp edge will last one or two cuttings, depend on conditions, and is not needed. No factory blades are that sharp or need to be. All factory blades have a .020-.040 thick edge. As I said if it works use it, but to others, you should some things to accomplish a better job.
Click to expand...
If you read the description in my video I mention to scrape the blade clean first,this is just a basic video,not professional at all.Yes it works for me,been doing it for a long time and my lawns look prime.Also Im just removing burrs when I go across the bottom lightly not changing the angle at all,,my blades last 15 hours no problem...they are still cutting good after that but could use a slight edge.


#6

5

577jersey

ILENGINE said:
The world largest blade manufacturer Oregon, uses what they call the 30-30 rule. Angle is ground at 30 degrees and leaving a .030 blunt cutting edge. No need to make a razor edge, which will immediately wear off,
Click to expand...
Of coarse there is no reason for a razor blade edge,,this is just the way i do them and wanted to share my 28 years of experience thats all.They cut great all week long doing 30 plus lawns.By the end of the week they are probably close to factory sharp..lol


#7

John R

John R

Thanks for the demo.


#8

5

577jersey

John R said:
Thanks for the demo.
Click to expand...

No problem my friend glad you like it,
I just wanted to share the way i have been doing it,and it works great...they cut better than new blades for a few days then the edge gets a little beat but still cut good for another few days,,and Im talking cutting all day long every day :)


#9

5

577jersey

bertsmobile1 said:
Nice video.
Just one point.
If and only if you lawn is clean with no stick, stones or protruding roots should you put a sharp edge on a ride on blade.

A "razor edge" will cut better and cleaner but will dull very fast and dent badly when it strikes anything other than nice soft clean grass.
Click to expand...
I have a couple spots on my trim side that hit a thing or two,after two or three touch up sharpenings the blade looks good as new,sticks wont damage the edge from my experience only rocks,wire,metal ect...the blades I use are XHT and are super hard.
This method probably wont work for everybody but it works great for me and my application here in the North East.


#10

O

oldyellr

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?


#11

5

577jersey

oldyellr said:
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?
Click to expand...
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.


#12

O

oldyellr

577jersey said:
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.
Click to expand...

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.


#13

5

577jersey

oldyellr said:
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.
Click to expand...
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


#14

B

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.


#15

Carscw

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.


#16

O

oldyellr

577jersey said:
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
Click to expand...

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.


#17

O

oldyellr

bertsmobile1 said:
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.
Click to expand...
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. :(


#18

Maxrevs

Maxrevs

577jersey said:
Here is a quick video on how I sharpen blades...hope it may help somebody save $$ down the road!!
Click to expand...

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.


#19

5

577jersey

Maxrevs said:
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.
Click to expand...
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 :)


#20

5

577jersey

Carscw said:
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.
Click to expand...
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.


#21

Carscw

Carscw

577jersey said:
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.
Click to expand...

Look at it this way.
6 weeks = about 500 yards


#22

O

oldyellr

Maxrevs said:
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.
Click to expand...
I second that. For years I used a bench grinder for sharpening blades. Even when using a big industrial size one at work, I found it slow and it required continuous quenching so as not to overheat the blade. An angle grinder with just about any kind of cutoff wheel is much better. I discovered that method when I couldn't find a breaker bar long enough to remove one of my blades and decided to do it in situ with my angle grinder instead. Necessity is the mother of invention.


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