Sharpening bush hog blades

[slan]

I have about 25 hours on my Squealer SQ160 now and after taking about 12 achres from partly overgrown fields with apple, cherry, birtch, and other brush to a nice planed off look I think I might need to sharpen the blades a bit.

I hit some pretty big rocks here and there the first pass through and planed my fair share of high spots off so when looking at the blades the other day i noticed there are a few BIG dents and flat spots in the cutting edge.

The biggest would be about an inch long and into the edge about 1/8 of an inch.

How do you sharpen these bledes and get the big flat spots out?
I was going to take the big ball pein hammer on the anvil to at least bend the edge back to the profile.

Any tips you guys can share?

Thanks......

 

[Bird]

Some folks use an angle grinder to sharpen blades without removing them. I've sharpened some two different ways. In both cases I removed the blades, which wasn't a big deal for me since I had a pneumatic impact wrench. I've sharpened some using a 6" bench grinder, and I've also sharpened some using a 4.5" angle grinder with the blade locked in a vise.

And while I never had to do it, I'd probably try straightening the edge as you said, with a big hammer and the anvil, although bending them may weaken the metal, or even break it. Depending on how bad the blades are, I might just replace them. In fact, back when I had a Bush Hog Squealer, I was surprised that new blades were as cheap as they were, but that's been a few years ago.

If you have to grind off too much, or pieces break off, then blade balance may become an issue. Personally, for brush hogs, I simply "balanced" them by weighing them and ground enough off for them to weigh the same.

 

[JDeerekid]

If they aren't to bad I usually leave them on and just block the mower up or lift it up with the loader and lean it against the barn and take the angle grinder to it. If they have alot of gouges or notches in them I will take them right off and pound them out with the maul and then grind a sharp edge on it.

 

[MarkLeininger]

Ditto on the angle grinder. Like Bird said, blades are surprisingly cheap. Maybe get an extra set and do surgery on the old ones some cold winter day when there's nothing else to do.

 

[6string]

I sharpen mine with an angle grinder and leave about a 1/16 in. edge on them for cutting saplings, this way it will "shatter" the stump off even and not leave a sharp stob that will puncture tires. It will still cut grass.

 

[botayota]

What should the blade edge on a bush hog be like, knife edge sharp?
I bought a Bush Hog SQ160, and finally started using it this past week, after
cutting a field, and doing some brush beating I blocked the deck up to take a look at the blades. There was a couple nicks on the edges, but noting real bad, but touching the edge of the blade it didn't really feel that sharp, just like a blunt edge. Maybe I need to check the blades closer, but thought I'd ask here.

Tks,

 

[Crash101]

The blades are typically a blunt edge, they're not designed to shear grass blades like a finishing mower, rather they pulverize whatever they come in contact with. they sling around with a lot of speed and momentum. thats why nicks should be addressed as soon as practical. You don't want a nick to turn into a crack which in turn will vibrate into a split and soon the blade slings out in whatever directions it's heading when it came loose.

 

[Baby Grand]

What Bird, 6string & Crash said.

I take them off & use a big bench vise and a double cut flat *******. Same as for a dinged felling axe. Haven't had to address anything with the anvil ... yet (crosses fingers). Try to keep that 1/16inch flat, leading edge from getting too knife like - your tires will thank you.

If you do take the blade off, make sure you put some anti-gallant (moly disulphide or similar) on the bolt's shank & threads. That will reduce fretting and make removal the next time a lot less dramatic - I had to use a 6 foot long 2 inch gas pipe for a breaker bar the first time around.

-Jim

 

[Bird]

What should the blade edge on a bush hog be like, knife edge sharp?

Nope, as the others have said, they tear, pulverize, and shatter, brush and such. A knife edge would be quickly damaged, bent, nicked, or dulled in such use. I think the recommended edge is approximately a 1/8" flat edge.

Now of course if you happen to only use your brush hog for grass and weeds with no woody material or rocks, etc. and you want to sharpen the blades more like a knife or lawnmower blade there's nothing wrong with that.

 

[have_blue]

What should the blade edge on a bush hog be like, knife edge sharp?
I bought a Bush Hog SQ160, and finally started using it this past week, after
cutting a field, and doing some brush beating I blocked the deck up to take a look at the blades. There was a couple nicks on the edges, but noting real bad, but touching the edge of the blade it didn't really feel that sharp, just like a blunt edge. Maybe I need to check the blades closer, but thought I'd ask here.

Tks,

After years of trial and observation, here's what I've found is best for my situation. I mowed my 7 acres often enough that I have a few light weeds, among the grass.

I sharpen the blades very sharp on my Woods BB72, every time I mowed. It took around 15 minutes, just a touchup was needed.

I found that with very sharp blades, I could back the RPM way off from 540rpm. Instead of the cutter making a lot of loud banging and grinding noises, it makes a quiet swishing sound. Instead of exploding the grass into big fluff balls, it lays most of it down flat, where it decomposes quicker. The sharp edges last very well because of the low RPM, and not recutting the grass. Near the end of mowing when the blades become slightly dull, I can feel the horsepower (and fuel!) requirement going up slightly. Bottom line, very sharp blades make light brush hogging much more pleasant and economical for me.

Now,,, if you have rocks and bushes, or you let your weeds get out of control, I suppose it doesn't help much to sharpen the blades very sharp.

 

[john_bud]

The other guys have hit on it. If you want to cut brush, you leave a 1/16 to 1/8th inch blunt edge so the brush will shatter and DIE. If you want to cut mostly grass and weeds then sharpen up to a knife edge. It's all in the use you have for them.

I have not had great luck bending blades, they tend to snap for me. But then I seem to cut as many rocks and stumps as brush and trees....

jb

 

[Trainer]

If you know a blacksmith, he can heat and hammer an edge on the blades. Don't lose as much metal and can get a good edge.

 

[Granite Tractor]

Some folks use an angle grinder to sharpen blades without removing them. I've sharpened some two different ways. In both cases I removed the blades, which wasn't a big deal for me since I had a pneumatic impact wrench. I've sharpened some using a 6" bench grinder, and I've also sharpened some using a 4.5" angle grinder with the blade locked in a vise.

I just found this old thread - very useful! Any recommendations on what kind of saw blade to use for an angle grinder to sharpen blades?

 

[CobyRupert]

Just a "regular"" 4-1/2", recessed center grinding wheel.

 

[big bubba]

good advice here. personally, i am not an advocate of crawling under a mower and sharpening the knives. some do it very well...but one slip, and a face full of grinder. as mentioned, i use an impact wrench, remove, & use a hand grinder with knife clamped down. btw, you probably already know that most of the cutting on mowing blades occurs on the last 1/3 of the blade...you'll notice that by the dings on the blade itself. if you are willing to sharpen them as scheduled maintenance (for me that's 2-3 times a season) you'll get a better look and machinery will thank you for it. note that as outer edges become more rounded, the less effective the knives cut. have a sharpened spare set on hand would be my advice. & block that mower well before you crawl under there!!!