How and when to sharpen Rotary BH blades

[sandman2234]

Have_blue,
Thanks for the help, and yes carburizing was what I had in mind. It allows for alot of less desirable metals to be used and still keeps the flexible around for when you need it. Nothing worse than having a heat treater making glass out of your parts by making them too hard. I have used the heat treater here for parts when I was at the machine shop, but don't know if they are still in business. I need to look as I go out of town this morning, on my way to New Jersey. I have a piece of T-1* plate that I have thought about making blades out of, as it is a abrasive resistant metal, but it is just too easy to drop by the store and pick up a new set for the lawnmower, and I usually tear up a bush hog before I wear out the blades.
David from jax







*I think that is what it was called

 

[losilman]

Figured,[if mower still is workin when they do need some attention] would just take torch,cut bolts off,and put new blades on,seems the simplist thing to me to do.

With 30+ years of messing around with this kind of equipment I will share a bit of experience. Have sharpened and 'touched-up' a lot of blades in place with a hand grinder ...the easiest and quickest way to go. Have also replaced a few blades over the years ...so don't cut the bold head off. You will still have to break the nut loose. That bolt is a shoulder bolt that the blade spins on and the shank had a key pinched in it to hold it while the nut is torqued down. If yours is different , it's like none I've ever messed with.

Happy mowing! (or hogging as the case may be)

Larry

 

[seymojo536]

I sure hope after 4 years, they had figured it out. Welcome to TBN! I agree that doing them in place is the way to go. Why make extra work?

 

[GPintheMitten]

I sure hope after 4 years, they had figured it out. Welcome to TBN! I agree that doing them in place is the way to go. Why make extra work?

True, but after 4 years, there are a couple hundred more guys wondering the same thing.

 

[rd_macgregor]

I have to pitch in here. On my 72" Walco Whistler mower, I managed to break the metal bracket that keeps the blade from swinging a full 360 degrees (otherwise the two blades might be able to hit each other). I bought replacement parts, but could not get the bolts off. Socket wrench, nope. Socket wrench and hammer, nope. Socket on breaker bar, nope. Socket on pneumatic tool, nope. After hours of this, I finally gave up and drove it to the local garage, where they had it all ready for me by next morning!
Bottom line is that I'm NEVER going to try taking blades off to sharpen them.
Now all I have to do is replace the slip clutch plates and I'll be back mowing. This hasn't been a good equipment summer for me...but, at least there haven't been any injuries (not counting my manly pride, of course!)
BOB

 

[tcreeley]

I have a pulp hook that I heated in the forge so that I could tap the tip with a hammer and mushroom it a little. (hangs on to wood better) I heated it to a low yellow, tapped, then I cooled it in water. When I was done, I had a fine crack running from close to the tip up toward the handle. That's no big deal in a pulp hook, in a bush hog blade- look out.
You never know with steel, unless you have the design specs in front of you. I once picked up a piece of steel from a scrap yard. I worked on it in the forge, then went to drill it on my drill press- but I couldn't do it. I couldn't get a hole going. (air hardening steel) Generally steel has to be heated, annealed (cools slowly in oxygen free environment -sand bucket, lime bucket, etc. - removes internal stresses). When cool, it is then tempered to the desired hardness.
A shop doing leaf springs and other stuff, know what they are working with and have worked in those factors. Give them a bush hog blade- no telling what you'll get back- can't see inside it! I wouldn't do it.

 

[lpdcac]

It is not difficult at all. Just raise it up, support it, and go to work on the blades. They don't need to be real sharp. Don't even crawl under there, just reach in with the grinder.

If you have the stuff to remove the blades, do so, and sharpen. Impact wrench, 1 1/2 socket, or whatever. There is a hole in the top plate with a cover. just for this.

The purists here will probably jump on me about this, but I generally stand my mower deck up and tie it off to a nearby tree. Using an air impact wrench I pull the stump plate [with blades attached] off and support it on some sawhorses. Gives me a better look at the blades and the stump plate as I grind the blades to a 1/16" flat edge. Note: There is a reason for pulling the plate. I mow for a neighbor and her pasture is riddled with rocks. One time I hit a rock pretty hard [don't know where that sucker came from - it wasn't there before] and bent the plate enough to have a bad vibration and a crack at the bolt hole. I may just be super cautious but it works for me.

 

[duke7595]

Got a 5 ft kk cutter that has 7-8 years on it just cutting grass and weeds,very little brush,no rocks,etc. Still does a fine job cutting, never sharpened blades.

Figured,[if mower still is workin when they do need some attention] would just take torch,cut bolts off,and put new blades on,seems the simplist thing to me to do.

Always sharpen my own lawn mower blades[got an old sears mower that I have shapened probably 10 times,same blades] so not worried about doing it,just figured to sharpen them right,would need to take them off hog,and if I was going to go through that probably painfull procedure,would just cut bolts off and put new blades on,than I'd be good for another 10 year??!!

The right bolts, washers and nuts aren't cheap. Best to either sharpen them in place or have the right size tools to take them off. I have taken them off before, if you soak them down the day before with liquid wrench they will come off. If not heat them and spray with liquid wrench, or your favorite penetrating oil and they will come off. However, the easiest way is to sharpen them in place with an angle grinder, just be very careful to support the B.H. good luck.