Let's talk about blade sharpening?

[Bange]

Well, for lack of experience with other machines and blades, I'm just talking about mine, but if it's not easy to discover the center of balance, the thing is impossible in my view.
In the past I had a small traction mower with a Teconseh engine (6HP), but I sold it in a short time and never sharpened its blade.

 

[sgkent]

the thing that concerned me is that blade was probably straight when new. If so a lot of steel has already been worn away. I would replace it and start over. Also the before photo shows a really blunt blade. Mine gets sharpened 2 - 4 times a year. When maintaining a blade it doesn't take much to keep it sharp, only a pass or two with the mill file. When it gets to be blunt then a lot of material must come off to sharpen it. That blade screams to me that it is time to replace it, but maybe y'all who work on these mowers all the time just see that as par for the course.

 

[ILENGINE]

I use an Oregon belt blade grinder aka Burrking 760 and a magnetic balancer. The Oregon blade sharpening recommendation is what is called the 30-30 rule which means sharpen at a 30 degree angle and leave a .030 blunt edge. All blades are wire brushed to remove all buildup and debris and for inspection. Worn or cracked air lifts get tossed and replaced with new blades.

 

[Bange]

the thing that concerned me is that blade was probably straight when new. If so a lot of steel has already been worn away. I would replace it and start over. Also the before photo shows a really blunt blade. Mine gets sharpened 2 - 4 times a year. When maintaining a blade it doesn't take much to keep it sharp, only a pass or two with the mill file. When it gets to be blunt then a lot of material must come off to sharpen it. That blade screams to me that it is time to replace it, but maybe y'all who work on these mowers all the time just see that as par for the course.

I believe that the use and quality of the grass and the ground determine the frequency of sharpening, as I said before, the previous sharpening was 50 hours of use (max 3 months passed)... in my space the lawn is still bad treated and the land is full of fruit trees such as coconut, mango, avocado, cashew... often the blade picks up something, in addition to the earth which is a real sandpaper.
Lower the deck less than 5cm... not a chance.
My space and mini tractor are old but I am new user without experience.

 

[Hammermechanicman]

I use an Oregon belt blade grinder aka Burrking 760 and a magnetic balancer. The Oregon blade sharpening recommendation is what is called the 30-30 rule which means sharpen at a 30 degree angle and leave a .030 blunt edge. All blades are wire brushed to remove all buildup and debris and for inspection. Worn or cracked air lifts get tossed and replaced with new blades.

Dang! You got a $3k Burrking.
Totally jealous. I just have the All American sharpener with an angle grinder with 36 grit flap disks. I built a wire brush blade cleaner from a table saw motor but it makes such a mess I don't use it much. If my shop was bigger I would get something better but I am so crowded now no room for anything new.

 

[Bange]

I use an Oregon belt blade grinder aka Burrking 760 and a magnetic balancer. The Oregon blade sharpening recommendation is what is called the 30-30 rule which means sharpen at a 30 degree angle and leave a .030 blunt edge. All blades are wire brushed to remove all buildup and debris and for inspection. Worn or cracked air lifts get tossed and replaced with new blades.

Another sharpener... very good...
For mowing the grass itself, I see no difference between 45 and 30°, other than less material removal...
Of course, different damages that can't be resolved with sharpening, blade for the trash.
But what does "leave a .030 blunt edge" mean?

 

[MParr]

I freehand sharpen with a 4” angle grinder with a 40 grit flapper wheel. I have a cheap 2 piece Oregon balancer. It gets the job done. I have to put sharp blades on around every 12 hours. I cut 3 acres once a week.
By the way, the OP needs new blades.

 

[Hammermechanicman]

You can sharpen to a razor edge but after just a few minutes of mowing the edge will round over to around ,030 so no need to sharpen to a razor edge. Look at the edge of most any new blade and it is not sharp like a knife.
There are some commercial guys that change blades every day and sharpen to knife edge so that when they cut rich people's yards the grass cuts ends stay green. Dull blades rip the grass and the ends turn greyish..

 

[StarTech]

Another sharpener... very good...
For mowing the grass itself, I see no difference between 45 and 30°, other than less material removal...
Of course, different damages that can't be resolved with sharpening, blade for the trash.
But what does "leave a .030 blunt edge" mean?
View attachment 64049

Well you are on the wrong train of thought here as the 30 degrees is right the opposite of your drawing. In your drawing the edge is too blunt and basically doesn't sharp very long.
Now the angle as shown below is a lot closer to factory edge. And of course you don't need a razor sharp edge as it dulls rather quickly anyway.

 

[Bange]

MParr and Hammermechanicman.

What is your sharpening angle?