Sharpen Brush Hog

[kenmissouri]

I have an old Howse 4 foot Brush Hog and have always sharpened the blades with a 4" grinder with the Hog raised on the tractor and blocked up. The downside is that a 4" grinder really only gets the ends of that hardened steel and never truly grinds down the entire taper of the blade like it should be done. My taper now looks more like a rounded off end. A 7" grinder is too big to safely get in there.

I don't have the equipment to take the blades off. If I did get them off they'd probably not go back on tight enough for safety.

Suggestions welcome!

 

[dtd24]

maybe a different blade!!!!!!!!!

 

[scott_vt]

Mornin Ken,
Bigger Bush Hog !

All kidding aside, I have always used my Dewalt Angle grinder 5". But the better method would be to get the equipment to take the blades off, and use a large belt grinder to get the blades the way you want them ! Like I said I usually just use the angle grinder, and call it good enough. My fields grow rocks during the winter and I usually find them on the first mowing, so no reason to get too fancy !

 

[RoyJackson]

All my Land pride manual calls for is a 1/16th chamfer on the edge of the blades.
You know these cutters pulverize more then cut, right?

 

[BB_TX]

Ken - If you have an FEL, use a chain and tilt the cutter up on its side so you can easily get to the full length of the blades. Make sure it tilts back and leans against the FEL with the chain tight for safety. Mine is a 6' Howse and I also use an angle grinder. Also makes it easy to inspect the underside and free up the blades if they are stuck. See pictures.

 

[yekrut]

BB_TX,

Great idea. I have a new L39 on the way and can't wait to use the FEL to do the same. Been tryin' to figure out how to sharpen the BH for a while now but I have asways come to the conclusion that it's either to dangerous or too much work for the gain I'd have.

 

[Highbeam]

You can do anything with a standard 4.5" grinder. It just takes longer. Get your ear plugs and glasses and have a seat. Start grinding until you get the profile you want. It seems that the last inch or so of blade does all the cutting anyway, right? I just grind out the big mushrooms and try and feather them in to a decently sharp edge. Yes, new blades have a longer bevel but that is jsut because I don't see any reason to sit there and grind off all of that metal behind the edge on a blade designed to chop. It's like a weedwacker string. Not sharp to slice but speed and mass to chop.

 

[Soundguy]

Perhaps a die grinder or air grinder with a grind stone would be easier to manuver for you.

I use a 4" grinder to do my 5' KK hog, as well as my 10' and 15' mowers.. never seemed to be much of a problem..

Soundguy

 

[sandman2234]

Sitting on a stool behind your tractor loaded on a trailer gets it high enough to deal with. Leave the bush hog sticking out past the end of the trailer so you have more clearence underneath but far enough forward if it drops it will contact the trailer instead of going all the way to the ground.
David from jax

 

[greg_g]

Hey - we're only talking four footer here. On my five footer it's easily a one man job to remove the crown nut and take the blades clean off the mower. Once removed from the center disc, an 8" or 10" bench grinder does a better job of returning the correct cutting angle to the edge. If you don't have a bench grinder that big, clamp the blades in a bench vise and go at them with your 4.5" angle grinder.

//greg//

 

[Tom_H]

If this model is Heavy Duty, then I agree with Roy Jackson. I could see sharpening the blades on a light duty. On a Medium Duty, I'm not sure. On a Heavy Duty, the blades function more like hammers than like knives; using the tremendous inertia, they simply break (or "pulverize" as Roy puts it) material rather than cutting it. Thus a sharp edge isn't all that necessary on a Heavy Duty model.

 

[greg_g]

C'mon guys. Does anybody here believe there's such a thing as a heavy duty four foot rotary cutter? With the right tools and technique, it should be a simple matter of putting a new edge on the blades off the machine.

//greg//

 

[John_Mc]

If this model is Heavy Duty, then I agree with Roy Jackson. I could see sharpening the blades on a light duty. On a Medium Duty, I'm not sure. On a Heavy Duty, the blades function more like hammers than like knives; using the tremendous inertia, they simply break (or "pulverize" as Roy puts it) material rather than cutting it. Thus a sharp edge isn't all that necessary on a Heavy Duty model.

I'd agree with that if you are actually cutting brush (e.g. saplings and the like). If you are cutting grass, having some sort of edge gives a much better cut. As someone else mentioned, when my blades get really beat up or rounded off, I'll grind them back to about a 1/16" edge.

John Mc

 

[Highbeam]

I don't consider the heavy vs. medium vs. light duty nature of the mower to make a rat's poo of difference IF you are cutting a normal pasture. If cutting known pasture then I tend to want the sharper blades just so that the finish is nicer. If cutting heavier trash like saplings and bushes then the bluntness of well worn blades is not a problem.

I do like Sandman suggests before I go to a pasture mowing job and grind the blades as they hang off the back of the trailer. The dovetail of my trailer allows me to get good access with the mower deck firmly dropped down onto the trailer and even chained down. There's plenty of room between the blades and the deck to get the typical grinder in there and I see no need to remove the blades for sharpening. That said, if I have to remove the blades for some other reason then it is really nice to sharpen them in the vise with the same 4" grinder.

 

[lopezian]

All, What about balance? Do you guys worry about getting the two blades to balance out? That would be especially hard for those of you who don't take the blades off to sharpen them.

If you do balance them, how do you do it?

 

[JerryG]

I know several post about sharping BH blades here all the time, but I have never sharpened a set. I use them until they are worn out and then put new blades on. I usually put new blades on each spring. The amount of rocks maybe the reason that they are completely worn out in a season. Flint rocks are hard on cutter blades.

 

[sandman2234]

Balance a blade that spins at 540? I guess you can, but I never have. I just try to cut about the same amount off each side, but for some reason, I don't think it matters. I bought a bush hog many years ago and wondered why it seemed out of balance. Turned out to have two different sized blades on it. Not even close to each other. I bought a new one and installed it and it was fine from then on, dispite the fact that one had been sharpened several times by the time I added the new blade to the other side. Maybe I am lucky or just don't notice it as much as others do.
David from jax

 

[Farmwithjunk]

Here's what works for me. Your results may vary.

4-1/2" right angle grinder will do the trick. It takes a little "elbow grease" every now and then. A new disc helps. I've rejuvinated some mighty beat up blades that way. I can't recall ever removing a blade to grind it. By the time I get out all the tools, I can be done grinding them in place. Generally do the task with mower hanging over the end of a trailer, or raised with 3-point hitch and jack stands/6"X6" timbers supporting mower. I NEVER allow myself to get more than one arm under the mower, and that's once it's properly shored. I hold the blade with a pair of 16" Channellocks. (Grinder disc's will do a number on flesh)

I replace blades every spring, obvious need for it or not. I've seen what happens when a blade breaks. Gruesome is too mild of a word.

The frequency of need for sharpening depends of course on how much you mow and under what conditions. I'm in rock country. Blade edges get hammered. The trick is to keep them touched up and NOT let the blade get too far out of shape. Excessive grinding is avoidable.

I don't see the difference in light/medium/heavy duty mowers and how the blades are ground. I grind my blades to one profile no matter what sort of mower I'm using. It's far easier to be accurate with a certain degree of consistancy from blade to blade. Just like swinging a golf club. The same exact way every time.

I've never balanced a bush hog blade. No need.

 

[kenmissouri]

It's a cheap light duty hog but still works like me. It appears most others use the same 4 or 4 1/2" grinder I have. My uncle had the brush hog before me and used a 9" grinder (way, way too dangerous for my tastes). Sharpening off the end of a trailer works sort of unless you have one of those mesh lift gates. They make it hard to block up the hog or get a stool in. The hog does pulverize more than it cuts, granted. That said, cutting grass in a pasture, sharp blades make a better "cut, flail, beat, pulverize".

I do have an FEL but almost never have it on the same time as the hog. It's too dangerous to have that extra front end versus rear weight in uneven situations, even with filled tires.

Does anyone know the correct torque for the blade bolts? Half inch drive is the largest impact wrench I have, 120-150 ft lbs +/-. That way a major reshape (or that expensive word I have trouble with "replace") could be done every couple years.

 

[N80]

I don't remember the specifics, but getting the blades off my JD LX-6 seemed like too much trouble and I don't think I have the necessary tools. Don't remember details but there is a nut somewhere that requires a lot of mechanical muscle to get undone.

I sharpen mine occasionally. I just tighten the top link all the way, back under the skinning rack, raise the mower as high as it will go and chain it to the top of the skinning rack for safety. It is a little cramped but I've had no trouble using the 4 inch angle grinder. Like others, I don't really sharpen them, I mostly just take the big dings and bulges out.

As for mowing with the FEL on, that's the only way I do it. It is easier to maneuver in tight places with it off, but I think it is actually safer with it on, both in terms of balance, and finding objects in the mower path. And its great for knocking down ant hills before the mower hits them. This, in turn, helps keep the blades sharper over time!