Opinion on to sharpen or not to sharpen a brush hogs blades

   / Opinion on to sharpen or not to sharpen a brush hogs blades #1  

new jersey mike

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Apr 22, 2009
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Location
NJ Home with property in East Worcester, NY
Tractor
2010 - NH T1530
I have read in the past the difference in opinion to sharpen or not to sharpen the blades. I believe I have found most of the rocks located on my property but of course there is always more. Attached is a pic of just one of mine on an sq172 . I am beginning to consider the balance issue with regard to stress and wear of the seal and bearings.

I have never taken the blades off how difficult would it be? I could use a hand held grinder but I would not know if the blades were out of balance.
 

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   / Opinion on to sharpen or not to sharpen a brush hogs blades #2  
Mike....I sharpen my blades only when they are pitted like yours....I lift the bush hog up and support it and then use my 4&1/2 inch hand grinder to smooth and flatten out the dents in the blade...you don't want it sharp like a knife..just a good square sharp edge....I would not take the blades off....it is a pain and you may not even be able to get them off without way too much effort...I have always used my hand grinder and the blades are never out of balance since you are not taking that much off....Now if you took the blades off and really ran them through a bench grinder then you might take so much off you would have a balance problem....Anyway that's what I have always done in many years of cutting....
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades #3  
I think it is more a matter of staying sharp. Sure, you can sharpen them to a razors edge, but they will just chip and dull again pretty quickly, where if you have them not quite sharp the edge will not chip and you'll have a smoother cutting line without the nicks to catch on things. A smooth edge is important, as a rough one will catch on things and tear them instead of cutting them in a smooth action.

Balance, on the other hand, is important. If you can feel an imbalance, remove them and weigh them, removing metal until they match. Your bearings will live longer with balanced blades.

If you can't feel an imbalance, sharpen them in place with an angle grinder. Spin it up to test for balance, then adjust accordingly.

Sent from my SCH-I500 using TractorByNet
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades #4  
The blades can be removed if you have a large socket. Mine are 1 5/8" nuts on the blades and 2" on the stump jumper. I just tightened them all up a bit on my yesterday. Removing the blade is easier if you can turn the mower on its side but it is still a two man job to reinstall them since the nut goes on from the top but you have to install the blade and bolt from the bottom. You should have a round hole about 2-3" in diameter usually in the back of the deck behind the gear box which is where you access the nuts holding on the blades. I have seen mowers without this hole and when changing the blades the hole has to be cut in the deck or the whole stump jumper has to be removed but this is P-Poor design. You can likely get them off by yourself, but may have trouble keeping the blade and bolt secure while transitting to the upper side to install the lock washer and nut. This is where you need a buddy. The bolt is self locking and wont turn so no need for backup under the deck when removing. I sharpened mine once after hitting lots of rocks and they were easy to remove. I wanted to check the attachment under the stump jumper so I took the whole thing off then removed the blades. The reason I wanted to check my attachment hub was because my brother in laws had broken the weld where the blade attachment piece was welded to the hub that attached to the gear drive. His was being held in place soley by the stump jumper. Mine was OK and I only had to repair his. Unless you take a whole bunch more metal off one than you do the other, you shouldnt have to worry about balance. Just sharpen them both the same way and it should be as good as new. I would leave at least 1/16" of face on the bevel when sharpening and wouldnt worry too much about trying to remove the gaps. It isnt supposed to be a finish mower so a little gap here and there isnt going to hurt the mowing appearance.
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades
  • Thread Starter
#6  
What do you mean by square sharp edge? or do you mean straight edge with no dents? And if you do mean with no dents, how much do you grind, the other blade has one very deep dent would you grind to that depth?

Mike....I sharpen my blades only when they are pitted like yours....I lift the bush hog up and support it and then use my 4&1/2 inch hand grinder to smooth and flatten out the dents in the blade...you don't want it sharp like a knife..just a good square sharp edge....I would not take the blades off....it is a pain and you may not even be able to get them off without way too much effort...I have always used my hand grinder and the blades are never out of balance since you are not taking that much off....Now if you took the blades off and really ran them through a bench grinder then you might take so much off you would have a balance problem....Anyway that's what I have always done in many years of cutting....
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades #7  
Pretty much like Brin, though in some cases of significant damage like others, I have taken them off. "normally a "touch up" in place with a 4" angle grinder, your manual will tell you something like 1/32/ 1/16 or whatever.
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades #8  
From the debris underneath, looks like you are cutting lots of fine grass. I would sharpen and the angle of the blades to be dependand on how confident you are that you've gotten the rocks. Sharper and more of an angle if you're confident, less sharp and an angle closer to square if not.

I think you can obtain a reasonable approximation of balance, once the blades are off, by bolting the two blades together and trying to use the bolt as a pivot, or better yet, using a piece 1" pipe or larger (fully threaded, short nipple) with a couple of fittings on each end to serve as nuts to cince down and keep the blades straight. Then balance on your fingers or a rod, stake, whatever that will fit through the hole.
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades #9  
What do you mean by square sharp edge? or do you mean straight edge with no dents? And if you do mean with no dents, how much do you grind, the other blade has one very deep dent would you grind to that depth?

Mike....No , if you have a real deep gouge or dent don't worry about one or two...what I do is square off the edge about 1/8 th. of an inch thick...you want the blades to crush the stems not slice them and then you would puncture your tires....the sharp blade would leave sharp Punjai sticks.. I just smooth out the edge and only go as deep as the majority of gouges on the blades...again, I personally do not take the blades off...it is just too easy to use the hand grinder...twice I have taken the blades off....and God Bless those that say they come off easy...both times it took me several hours with an impact wrench and torch to finally get the blades off....Should be fine on the balance...I always have been.
 
   / Opinion on to sharpen or not to sharpen a brush hogs blades #10  
I have the same BH...found it impossible to remove the blades.Impact wrench....three ft.cheater!!!!!!.I ended up raiseing and doing from below.You don't want them sharp like lawnmower blades.Leaves a lot of "pungi" stakes.Leave them square about 1/8 in.,this shatters the brush and does'nt leave as many sharp pointy's.
 
 
 
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