Sharpen bush hog blades??

I just had to buy 2 new blades for my bush hog, that I have had since 2000. This is the 3rd set of blades in 20 years. The new blades are somewhere, around 3/8" thick, and beveled some at the cutting edge. They are still 1/4 " thick, on the cutting edge. In the past I have sharpened the cutting edge, with a 4" grinder, and it is quite a job. Are you guys sharpening your new blades, or are you running them, as they come, from the store? Within a year, they are in poor shape any way, and need sharpening again. And one other thing, would it be worth while to put hard surface rod on old blades?

I currently have four rough-cut rotary mowers all of which I use as HD finish mowers. Accordingly, I keep the blades sharp on all.

I've bought many replacement blades for various brands of rough-cut mowers from multiple sources. All of the replacement blades that I have bought have been "semi sharp" (1/16" or so) as purchased. Still, I sharpen to near lawn mower sharpness before installation. No, I do not hit rocks, stumps, etc., and I do not cut saplings.

Sounds like you need a new source for replacement blades.

I once spent hours sharpening the unsharpened "edge" of a slip scoop to a 45 degree or so edge. Doing so wore out a (cheap) HF 4" grinder and several wheels.

If you hit hard objects, put them on and forget about it. If you do not, get another set or spend the time to sharpen the ones that you have.

Sharp blades cut better and require a bit less HP and fuel.

Dean

I try to keep mine sharp. Much easier on the tractor and does a better job when it can cut instead of beat.

So far, I disagree with everything I read here. I have been doing heavy duty cutting for 23 years with a Land Pride RCR3572. 1/2" by 4" blades. I do hit rocks as evidenced by the dents in the deck. We have rocks. How can I not hit a rock once in a while in 23 years. I chop box elder saplings 3" thick, sometimes more. I use the mower to clear fence line brush. The only time I sharpen blades
is when they get blunted over on the leading edge from, you guessed it, rock strikes. Normal cutting including rock strikes gives them a jagged leading edge which actually cuts grass just as good and maybe a little better than a smooth leading edge. I'm on my third set of blades, in 23 years. The second set was destroyed in a massive stump strike. Stump was concealed by brush, weeds and grass. Those things happen. If I want a really good smooth cut in grass, I back up. Now that really drives guys on this forum ape. Gives a much closer, cleaner cut and the replaceable skids don't dig in. They just glide along smoothly due to much lesser angle of attack. And no, I don't change the oil in the gearbox. It doesn't even have a drain plug. One guy told me he changed his gearbox oil every year. I asked how. He said he opened the add oil plug and hung it on the shed wall. Crazy. I'm not going to hang a 1300 lb mower on my shed wall. My rant but I have a lot more mower facts. The more mower facts, the better. (;>))

One other thing to consider if you have any local blacksmiths. They can sharpen blades without removing metal.

Back in the good ole days a blacksmith forged car leaf springs to a set of worn out blades for us. They lasted longer than the originals.

If you are cutting saplings you are better off leaving the dull that way the stump will be shattered, if sharp you will get a clean cut and the next time you mow they will puncture your tires.

Pete

I bought a set from TSC they were dull as a hoe, I sharpened em up with a 7 1/4 grinder, cut like a lawn mower

Have seen some that were so bad they looked like beating stuff off ballbat. Just cut new edge with torch.

I mowed for the Kent County Airport. We had about 2,000 acres to mow. The sharper the better when it comes to just grass or tall weeds. When actual brush is involved a little duller seems better. We always used a 7 1/2" portable grinder to keep our blades sharp. I used a 15 ft. Bat Wing on the back of a Ford 5,000. PTO driven and hydraulic actuated to raise and lower for height.We used smaller 10 ft. mowers for close in to the Terminal area on the A.O.A. side of the field.

Sounds like just what I said except that I've been cutting just about everything at one time or another for going on 50 years.

Dean

(quoted from post at 20:16:43 06/19/20) Sounds like just what I said except that I've been cutting just about everything at one time or another for going on 50 years.

Dean

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Is your reply somehow more important because you think youve been at it longer? No need to be rude, everyone is trying to help.

(quoted from post at 14:25:03 06/19/20) I just had to buy 2 new blades for my bush hog, that I have had since 2000. This is the 3rd set of blades in 20 years. The new blades are somewhere, around 3/8" thick, and beveled some at the cutting edge. They are still 1/4 " thick, on the cutting edge. In the past I have sharpened the cutting edge, with a 4" grinder, and it is quite a job. Are you guys sharpening your new blades, or are you running them, as they come, from the store? Within a year, they are in poor shape any way, and need sharpening again. And one other thing, would it be worth while to put hard surface rod on old blades?

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In my experience what you are observing is NORMAL, and if you look at the Operator's Manual for many rotary cutters they will advise to sharpen the blades in a similar manner, leaving a blunt edge.

If you want to make 'em sharper with a grinder, HAVE AT IT, and if you want a "golf course cut" you should be using a "finishing mower".

I've never put new blades on mine. When I do sharpen them I use an engine hoist and lift it up while still on the tractor and go under it with a creeper and sharpen the blades with an angle grinder.

Gees I know they quit sharpening blades for fear someone will cut themselves and sue but 1/4", that's awful.

I agree with PI Pete, leave them dull save your tires! We have so many rocks it's a waste of time to try to keep them sharp. I do go over them with a grinder once in a while, they get pretty beat up. We have a Farmall C with a Woods belly mower, I keep those blades sharp for grass.

Gear box oil change.

That's what they make suction guns for.
maximum suck

Back when I had a bush hog (Howse brand), I kept the blades with a little bit of edge as I was normally cutting field grasses, etc. When I needed the mower for brush, I preferred a dull (even blunt) blade. Having a sharp cutting edge would leave stalks and sapling trunks with sharp tops that could cause all sorts of damage, to tires and to animals/people.

PI pete and Russ from MN have it right. If you are cutting pretty much just grass go ahead and sharpen them.

I find that there is a certain point whereas they get beat up too much, just replace them. I do sharpen, but also replace when I see they need it. I just cut a field with a new set on, bunch of work done to the mower and it cuts very nicely, also, no vibration because they are balanced. Over time, with sharpening, they will get of balance and you may see the deck with a slight wobble or vibration or worse. New blades and just raise up over questionable areas, no need to cut close, you can do that on a subsequent pass, after you see what's there. I know all the areas I cut, but unknown areas will get cut high on the first round and or inspected first.

Thanks for pointing that out. I haven't seen one of those in years, in fact, I used to have one that I used to put oil into a car transmission that was hard to get to. Wouldn't that still present the problem of filings in the bottom that wouldn't get sucked out? Maybe a magnet. I have a small magnet about the size of a watch battery on a long screwdriver type handle.

(quoted from post at 14:25:03 06/19/20) I just had to buy 2 new blades for my bush hog, that I have had since 2000. This is the 3rd set of blades in 20 years. The new blades are somewhere, around 3/8" thick, and beveled some at the cutting edge. They are still 1/4 " thick, on the cutting edge. In the past I have sharpened the cutting edge, with a 4" grinder, and it is quite a job. Are you guys sharpening your new blades, or are you running them, as they come, from the store? Within a year, they are in poor shape any way, and need sharpening again. And one other thing, would it be worth while to put hard surface rod on old blades?

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I use a 4" angle grinder and make mine serrated, much easier and cuts fine. I got about 900 hours out of this set. You don't cut bread with a smooth knife....

My trash mower (Landpride) is used for rough cut only. Way too many rocks, saplings and other trash to keep the blades real sharp. I believe 1/4" is normal. I use a finish mower for the lawn. These blades are sharp but there are no rocks or other trash to hit in my lawn.