Sharpen shredder blades or buy new?

   / Sharpen shredder blades or buy new? #1  

tmc_31

Gold Member
Joined
Nov 21, 2005
Messages
394
Location
Texas
Tractor
NH TN70D, NH L190
Hello all,

I have a 5 year old Rhino SE7 rotary mower that I need to either replace or sharpen the blades on. I have owned the mower since it was new. Up until recently I have only used the mower 3 or 4 times a year mowing less than 5 acres each time. I looked at the blades the other day before I started a mowing job and they seemed pretty dull with a few nicks taken out of them.

Can I resharpen these blades? I have the operators manual, which recommends sharpening the blades down to 1/16" at the cutting edge. Has anyone done this? How often do you do it, or do you just replace them when they get dull. Is it it best to grind them? I have a vertical mill that I think I could set the blades up on and mill the new cutting edges with a carbide face mill.

The original blades are 28-1/4" from the tip to the center of the mounting hole and 4" wide. I can buy new blades from my NH dealer but they seem pretty expensive. I found some at TSC that were the correct length but only 3-1/2" wide. How critical is it that I get the exact same blades as original? My operators manual just gives a part number for the blades and the bolts/nuts, no description. Anybody know where I could find a good description of the blades and bolts?

Thanks,

Tim
 
   / Sharpen shredder blades or buy new? #2  
First, you should follow the manual and what the manufacturer recommends. Typically you do not want "sharp" blades that cut.

The leading edge on mine are a blunt 1/8th inch per the manual.

Do a search and you'll find a couple of past threads on sharpening the blades.
 
   / Sharpen shredder blades or buy new? #3  
a hand angle grinder works good. :thumbsup:
 
   / Sharpen shredder blades or buy new? #4  
We use a 4" angle grinder to put the recommended edge which as mentioned is not "sharp".
 
   / Sharpen shredder blades or buy new? #5  
I agree. dont need anything more than an angle grinder, you dont want to make "tire poppers" you want to shred the tops of any brush, not leave a trail of pungi sticks behind you.
 
   / Sharpen shredder blades or buy new?
  • Thread Starter
#6  
Hey all,

After posting this, I did as greasemonkeyok suggested and searched this forum for threads about blade sharpening (sorry, I should have done that first). As he said, there are quite a few relevant threads and many ideas.

I went back again to the operators manual and verified the recommended blade thickness at the cutting edge, sure enough Rhino recommends 1/16" for this shredder. I also called my NH dealer, he has a new blade set for $95.00 and a new bolt kit for $45.00. He did tell me that the nuts for the blade bolts took an 1-1/2" socket. I will be checking other places for blade and bolt sets as the prices from my dealer seem a little high. In the meantime, I guess I will sharpen what I've got and see how that works.

Any additional information you may have will be appreciated.

Thanks,

Tim
 
   / Sharpen shredder blades or buy new? #7  
Hey all,

After posting this, I did as greasemonkeyok suggested and searched this forum for threads about blade sharpening (sorry, I should have done that first). As he said, there are quite a few relevant threads and many ideas.

I went back again to the operators manual and verified the recommended blade thickness at the cutting edge, sure enough Rhino recommends 1/16" for this shredder. I also called my NH dealer, he has a new blade set for $95.00 and a new bolt kit for $45.00. He did tell me that the nuts for the blade bolts took an 1-1/2" socket. I will be checking other places for blade and bolt sets as the prices from my dealer seem a little high. In the meantime, I guess I will sharpen what I've got and see how that works.

Any additional information you may have will be appreciated.

Thanks,

Tim

This actual experience may help in your decision....I have been using my bush hog brand bush hog to cut about 14 acres at least 3 times a year for 7 years now and I have the same blades and have used a hand grinder to sharpen them according to the manual only 3 times in those 7 yrs. Look at your blades and unless they are bent or severely worn they do not need replacing. I do not remove my blades to sharpen them...I just block up the bush hog and slide under there with my grinder. On another bush hog I replaced the blades once ...It was not fun...those bolts get stuck in there ..even after you get the nuts off...the bolts themselves have gotten stuck..It took me a good 3 hours to get it done..I had to use a torch to heat them up....
 
   / Sharpen shredder blades or buy new? #8  
According to the math they have maybe 100acres cut with them.

If they are not bent, cracked, broken then it would be a waste of time and money to replace. Dress them up with an angle grinder and roll on.
 
   / Sharpen shredder blades or buy new?
  • Thread Starter
#9  
Went to TSC this afternoon and bought a 1-1/2" 3/4 drive socket (already had the 3/4 breakover bar and short extension). Put a 5' cheater over the breakover bar and the blade nuts loosened right up (read about the 5' cheater in a previous post). Before I drove in to TSC I did squirt the nuts liberally with WD40.

We're on our way!!

Tim
 
   / Sharpen shredder blades or buy new? #10  
I replace mine with new ones. I seem to hit unshreddable things often enough that it would take some serious grinding to get old ones back into action.

For those who re-sharpen, what do you do, to make sure the two blades stay the same weight and balance?
 
 
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