Let's talk about blade sharpening?

[*CPB*]

Attention sharpeners...
No answers!?!?!

If you live in an area where the soil is sandy then to me that's a whole 'nother animal. Over the years I've seen pics of the effects sand has on blades and it's just crazy the way the metal gets eaten away. If that's your situation then I would just sharpen regularly and then recycle them long before they look anything like the ones in these pics....



If you don't have sandy soil and are only cutting grass and not hitting a bunch of foreign objects then your blades should last years with regular sharpening, IMO. I have blades I've sharpened dozens of times and there's still plenty of life left in them. The pic below is taken from the Magna-Matic sharpener manual, and shows their opinion on the right and wrong way to sharpen a blade over the course of its life. I sharpened a blade last year that was getting close to looking like the bottom one. I showed the guy the picture and told him to get another set of blades. Although they don't explicitly say it, I believe Magna-Matic believes that you can sharpen the edge of a blade almost back to where the sail of the blade starts to curve upward. You can see that in the pic below as well. That seems to make sense to me.

 

[ILENGINE]

If you live in an area where the soil is sandy then to me that's a whole 'nother animal. Over the years I've seen pics of the effects sand has on blades and it's just crazy the way the metal gets eaten away. If that's your situation then I would just sharpen regularly and then recycle them long before they look anything like the ones in these pics....

View attachment 64171View attachment 64172

If you don't have sandy soil and are only cutting grass and not hitting a bunch of foreign objects then your blades should last years with regular sharpening, IMO. I have blades I've sharpened dozens of times and there's still plenty of life left in them. The pic below is taken from the Magna-Matic sharpener manual, and shows their opinion on the right and wrong way to sharpen a blade over the course of its life. I sharpened a blade last year that was getting close to looking like the bottom one. I showed the guy the picture and told him to get another set of blades. Although they don't explicitly say it, I believe Magna-Matic believes that you can sharpen the edge of a blade almost back to where the sail of the blade starts to curve upward. You can see that in the pic below as well. That seems to make sense to me.

View attachment 64176

Had a customer years ago that lived on a river bluff area and over time the sandblasting cut the bottom inch of deck off his JD.

 

[*CPB*]

Had a customer years ago that lived on a river bluff area and over time the sandblasting cut the bottom inch of deck off his JD.

Yep. I've seen pics of decks with no rust, but had areas where the sand had worn them so thin you could see holes forming.

 

[Roy405]

I don't know the correct way to sharpen a blade, but I'll describe mine... what's yours?

In fact, sharpening is not a very important item for many users, because even if the blade is not sharp, the cutter will shred the grass or any tree leaf... but the result is not satisfactory, in addition to causing greater consumption with more passes and even damage to the deck as a whole.
To those who don't sharpen, but change it after noticing an inefficiency, congratulations... it's the most correct way... but expensive.
Let's go...

With the blade off the deck, clamp it with a clamp on the workbench and clean (rust, glued and dry grass, animal manure, etc...), on all surfaces, using a grinder with flap disc, wire disc, etc.
After cleaning, I change the disk for an iron grinding disk (carburundum, diamond, aggressive flap, etc...) and grind at approximately 45° until I get a good edge.
After satisfactory sharpening, I move on to the balancing stage, an important procedure to keep the deck serene, without unnecessary vibrations that can cause loosening of screws, premature wear of pulley bearings, noise, etc.
To do this, just fix a rod with a rounded profile in a vise or workbench and hang the blade through its hole... the photos speak for themselves...

Cleaning the blade
View attachment 64029View attachment 64030
Cleaning up will make balancing easier at the end.

Sharpening...
View attachment 64031


Balancing

Blade one...
View attachment 64032
Very good...
View attachment 64033

Bade two...

Oops! Necessary adjustment...
Mark the side and remove material to make it lighter... preferably not on the sharp part.
View attachment 64036
View attachment 64036
View attachment 64038
View attachment 64039

Until equilibrium is achieved, several attempts can be made...

The end of the blade must be given special care, as it is the first to attack the grass... in any case, the edge is lost along the entire stretch due to stones, stumps, sand, sidewalks, hard fruit seeds and other objects. ..

What mower is that from

 

[Petriw]

Blade sharpening. What I do.

1. Clean the blade
2. Restore the edge with an axe file
3. Course first
4. Fine Next
5. Sharpening stone - Coarse
6. Sharpening stone - fine.
7. Neighbors like the way I do this!
8. Anyone want a shave?

 

[TobyU]

Blade sharpening. What I do.

1. Clean the blade
2. Restore the edge with an axe file
3. Course first
4. Fine Next
5. Sharpening stone - Coarse
6. Sharpening stone - fine.
7. Neighbors like the way I do this!
8. Anyone want a shave?

But exactly how long does it take you to sharpen the average blade like this?
Obviously a very dull blade is going to take long and one that's not nicked or chewed up or even that dull won't take long at all but how long does the average blade take you?

 

[TobyU]

It is worth noting how much certain conditions will chew up the blades.
Living near creeks I think is the worst and then woods is the second worst but I learned a long time ago how amazingly rough simply sticks and or pine cones were on a blade.
It makes sense that blades get chewed up if people have landscaping rocks etc and stones around that they will occasionally hit but you would not think small sticks the size of your pinky finger or pine cones would take big nicks out of blades but they do.

 

[Steve Smith]

I don't know the correct way to sharpen a blade, but I'll describe mine... what's yours?

In fact, sharpening is not a very important item for many users, because even if the blade is not sharp, the cutter will shred the grass or any tree leaf... but the result is not satisfactory, in addition to causing greater consumption with more passes and even damage to the deck as a whole.
To those who don't sharpen, but change it after noticing an inefficiency, congratulations... it's the most correct way... but expensive.
Let's go...

With the blade off the deck, clamp it with a clamp on the workbench and clean (rust, glued and dry grass, animal manure, etc...), on all surfaces, using a grinder with flap disc, wire disc, etc.
After cleaning, I change the disk for an iron grinding disk (carburundum, diamond, aggressive flap, etc...) and grind at approximately 45° until I get a good edge.
After satisfactory sharpening, I move on to the balancing stage, an important procedure to keep the deck serene, without unnecessary vibrations that can cause loosening of screws, premature wear of pulley bearings, noise, etc.
To do this, just fix a rod with a rounded profile in a vise or workbench and hang the blade through its hole... the photos speak for themselves...

Cleaning the blade
View attachment 64029View attachment 64030
Cleaning up will make balancing easier at the end.

Sharpening...
View attachment 64031


Balancing

Blade one...
View attachment 64032
Very good...
View attachment 64033

Bade two...

Oops! Necessary adjustment...
Mark the side and remove material to make it lighter... preferably not on the sharp part.
View attachment 64036
View attachment 64036
View attachment 64038
View attachment 64039

Until equilibrium is achieved, several attempts can be made...

The end of the blade must be given special care, as it is the first to attack the grass... in any case, the edge is lost along the entire stretch due to stones, stumps, sand, sidewalks, hard fruit seeds and other objects. ..

I agree with everything said here except I use a cone type balancer. I clean my blades by soaking them in warm water to loosen the material then take a wire wheel to them. It seems easer.

 

[TobyU]

I agree with everything said here except I use a cone type balancer. I clean my blades by soaking them in warm water to loosen the material then take a wire wheel to them. It seems easer.

Again, I'll go back to how long does it take you from start to finish to remove sharpen a blade and put it back on?
All this soaking, cleaning, wire brushing, scraping, blasting, etc is fine if you are the homeowner and you're only doing your blades once or maybe twice a season but even for someone working on mowers out of their home on the side for just friends and neighbors...this it's just far too much time and effort put into something that makes little difference to the end result or to the result after the next 15 minutes of mowing.
Now for many of us commercial guys who do many mowers a day, this would just be a real waste of time and effort.

There is a happy medium though between using the commercial strong grinders that eat the blades up so much that's unnecessary and doing them with a file. LOL

 

[Bange]

Saw this post in a daily email and intrigued me. Not a professional sharpener by any means, but I did invest in Magna Matic sharpener and balancer several years ago. If anyone desires to take a deep dive into the scholarly side of blade sharpening, take a look at the video below (be warned its almost an hour long, but very informative). Synopsis of video is keep a 30 degree angle...

Excellent information material... unless the center of mass is different from the center of rotation in some blades (if I understand it that way), because if the compensation is not in the same part (blade), there must be a counterweight connected to it axis to compensate for dynamic balance.
Is there really a blade with a center of rotation different from the center of mass? Which? Can anyone post or tell us what make/model… if it's for a specific type of lawn mower?

I was glad to know about the analysis of the straightness of the blades (24:01), as it is something I didn't even think about and will now move on to the first procedure item, before removing the blades.

The material also answered my question about how to proceed with material removal when sharpening (post # 27), making it clear that option “B” is the most correct.

Another important point was information on the sharpening limit, which is at the beginning of the curvature (22:01)... but what has already been said about the effect of sand, which thins the blade... so, what is the limit of the thickness?