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I'll be following this. I also have bahia grass in sandy soil and I sharpen my blades every other week. I mow 4 acres weekly and buy new blades every season. I just tried out the gator blades today and they work very well cutting but they sure throw a lot of stuff out of the chute. I had to clean the screen on the radiator 3 times today.
 

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Old Pa-pa
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I just checked the price on those suckers, WOW!!! :banghead:
 

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Discussion Starter #5
On mine by the time the blades need sharpening they've been sandblasted away to nothing. I just buy them in bulk on ebay and usually just replace them. Very very seldom do I have enough blade left to sharpen them.
The sand sure does do a number. I use a 4100 with mid-mount and ZTR's (757,797,960 and 997) on the property so have a lot of blades to sharpen. Currently I just run till the ends are gone and change them out. The grinder is pricey but replacing blades a couple of times a year for each unit is not cheap either.
 

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Discussion Starter #6
I'll be following this. I also have bahia grass in sandy soil and I sharpen my blades every other week. I mow 4 acres weekly and buy new blades every season. I just tried out the gator blades today and they work very well cutting but they sure throw a lot of stuff out of the chute. I had to clean the screen on the radiator 3 times today.
I cut about 35-40 acres every couple of weeks(actually an ongoing process each week with a few acres every other day). Lots of trees, ponds, buildings, fences , banks and ditches. I have a 5100M with MX7 cutter that I use on the wide open areas and when it 100 degrees outside!
 

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This little dude in expensive to own, when you consider how many mower blades it would take to pay for it. At $750.00 up front cost, and the cost of what three (average mower uses) blades averaging $50.00 per set you would sharpen, you would get 15 sets of blades to average the cost of the Magna-Matic 9000 unit.

I have a hand grinder and I sharpen the three blades on my 54" deck once a year in the fall after the mowing season. I own a JD 345 and a JDZ710A and I hate to sharpen these blades. Some times, I just buy new blades for each mower and pay the price(s). I buy Stens brand blades.
 

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And I was on the fence over an $8 sharpening kit from Home Depot. lol
It includes a grinding stone that fits a drill and a little plastic wobble piece to balance the blade.
Was paying $6 each to have the mower shop sharpen them. So it paid for itself already.
 

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I have found that a 4 inch angle grinder with a flapper style sandpaper disc gives me excellent control of the edge geometry for blade sharpening. The sanding discs allow very slight grinds or heavier metal removal if needed without throwing too much heat into the blade. I use a flat file to put a small flat on the cutting edge when I am done with the grinder. Not much money and fast results.
 

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Discussion Starter #11
This little dude in expensive to own, when you consider how many mower blades it would take to pay for it. At $750.00 up front cost, and the cost of what three (average mower uses) blades averaging $50.00 per set you would sharpen, you would get 15 sets of blades to average the cost of the Magna-Matic 9000 unit.

I have a hand grinder and I sharpen the three blades on my 54" deck once a year in the fall after the mowing season. I own a JD 345 and a JDZ710A and I hate to sharpen these blades. Some times, I just buy new blades for each mower and pay the price(s). I buy Stens brand blades.
I have always purchased my blades from my local John Deere dealer so I realize they are more expensive but like to support local business. I go through at least two sets for each mower each year so that equates to 10 sets of blades ( three 60" decks and two 72" decks). I have angle grinders and bench grinder but I am the worst at keeping a constant angle. Failed to mention that I have to send out the blades on my Bandit XL 065 wood chipper so another consideration and blades on two 84" rotary cutters (however have only replaced one set in last 10 years). Anyway, still on the fence with this idea. On the other hand, can never have too many tools!
 

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These re the mower blades I used on my JD Z710A 54" deck. They are 19" with 7/8" dia. hole...Same as the John Deere #TCU30327 High Lift factory ones. Cost from XHT is $42.63 set of three with free shipping. NOTE: The extra width on the cutting edges of these blades.

My deck came with the Mulching Kit and I left parts of the baffles brackets on the deck. I just removed the outer chute cover/bracket. All work well with me.


 

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Discussion Starter #13
I have found that a 4 inch angle grinder with a flapper style sandpaper disc gives me excellent control of the edge geometry for blade sharpening. The sanding discs allow very slight grinds or heavier metal removal if needed without throwing too much heat into the blade. I use a flat file to put a small flat on the cutting edge when I am done with the grinder. Not much money and fast results.
Do you use a jig or just eyeball it? As I posted, I am terrible at maintaining the proper angle so have probably messed up more blades than I have improved so the main reason I purchase new ones. Have a number of blades in my scrap metal stock that maybe could be salvaged. The old blades are maintained as sets in the scrap metal bin.
 

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I clamp the blade in a bench vise and take very light cuts to witness that I am keeping the primary angle intact. I don't feel that variations in the cutting angle are really that critical for cutting grass. I am more used to production metal cutting where a degree change can be proven to enhance or reduce performance dramatically.
A more abrupt angle will provide a stronger cutting edge that resists chipping or rolling over better than a shallow angle that will cut easier and cleaner but will chip, roll and dull sooner.
You could set a small machinist protractor or similar to the edge angle of a new blade and use it to check as you go. As I stated earlier, there is probably little consequence to not producing a perfect factory cutting angle.
 

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So, could you put the Magna-Matic money in a CD,
and get enough interest to buy new blades that you need? :dunno:

Surely, the $700 cost would buy a HECK of a lot of new blades,,,

I buy blades as I need them,,,,:good2:
 

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I have found that a 4 inch angle grinder with a flapper style sandpaper disc gives me excellent control of the edge geometry for blade sharpening. The sanding discs allow very slight grinds or heavier metal removal if needed without throwing too much heat into the blade. I use a flat file to put a small flat on the cutting edge when I am done with the grinder. Not much money and fast results.
Really like this post and your later follow up post.

Blades on my Z are still original Deere, 3 years old and still in good shape, no sand, rocks and any stick/branch over 3/8" in diameter
gets picked up.

Have been using just a file to maintain them.
Using a flapper disc sounds like a great way to sharpen with light pressure while not overheating the edge and
maintaining edge geometry.
Really don't want to use a 1/4" grinding disc on my 4 1/2" angle grinder.

Think I'll give this a shot next time around, lots cheaper than a $750 specialty bench grinder.
 

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I have a slight problem with mower blades on my two machines. It's how often I need to replace these blades. The JD345 with the 54" deck uses the same length blades as the JDZ710A 54" deck. Both with 19"-78" dia.
I mow 2-1/2-3 acres with the 345 all due to the three, shrubbery, and wife's flower beds, etc. The other 7 acres I use the Z710A as I can mow much faster and don't have the objects come into play.
I have to replace the blades on the 345 each year. It seems they wear out much quicker. It's probably the material of the blades that I must replace them. The blades on the Z710A is somewhat thicker and has a different cutting edge and design to them. I've own the 2012 Z710A since 2013 with 37 hours. Here it is 4 years and 332 hours later and I'm on my 2nd set of blades. Here is a photo of these blades that I install in 2015 and taken off last week to sharpen and clean the underside of the deck. These will go back on in the spring to be used again in 2018. You will see I have a good supply of blade left to use and sharpen.



 

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Discussion Starter #18
I clamp the blade in a bench vise and take very light cuts to witness that I am keeping the primary angle intact. I don't feel that variations in the cutting angle are really that critical for cutting grass. I am more used to production metal cutting where a degree change can be proven to enhance or reduce performance dramatically.
A more abrupt angle will provide a stronger cutting edge that resists chipping or rolling over better than a shallow angle that will cut easier and cleaner but will chip, roll and dull sooner.
You could set a small machinist protractor or similar to the edge angle of a new blade and use it to check as you go. As I stated earlier, there is probably little consequence to not producing a perfect factory cutting angle.
Thanks for responding. I went back and looked at six sets of old blades and really none of them could be salvaged due to excessive wear on the tips of the blades. A direct result of the grass and sandy soil.
 

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My Z920M came with the high-lift blades. When it was delivered I made 1 round around my yard (during a dry spell) and the entire machine (myself included) was covered in sand and dust. I immediately removed the blades and installed a set of the low-lift blades which made life much easier. There was no way my wife would have been able to operate it like that. (She insists on doing the mowing-I may have cut some flowers down at one time)
However the blades only last about 2 months at most and the up-turned "lift portion" of the blade is completely gone and the blade length is reduced by 1/4" overall. They then start leaving strips of uncut grass. Sharpening them only accelerates this wear and reduces the life even more. I usually go through at least 2 sets of blades each summer. I buy them off ebay and usually wind up with Stens or Rotary brand blades at around 100 bucks for 3 sets. (9 blades) I tried the expensive gator blades once and noticed no difference in cut quality or lifespan so I went back to the cheapest I could find.
Bear in mind I live in the mountainous tropical jungles of central Louisiana,(NOT the swamps), and the soil here is very sandy. The grass and jungle seems to grow about 3 inches a day and during peak mowing season we have to mow twice a week. About 4 acres.
 
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