I told a guy today that I'm getting into blacksmithing. He wants me to learn to sharpen his bush hog blades. I've spoken to a few smiths about it. The most recent conversation the guy told me he hammers the bevel at a steep angle that's almost flat according to him. He said he tried tempering them but found that they last just as long if you let them cool by throwing them in the driveway leaving them for a few hours. Any suggestions will be greatly appreciated.

It's just my opinion but I personally would not forge bush hog or any other mower blades because of the liability. Plows and such won't go flying off willy-nilly in the direction of people or things so it's no big deal to forge those types of tools - but all it takes is one broken blade to wreck a shredder or someone's leg. Other folks may do it all the time and never have a problem but I would decline that type of work.

I agree on not forging bush hog blades. Those things can make a real mess if something goes wrong. Just getting them properly balanced off of the machine would be a job in itself. I know if mine isn't right it gets pretty shakey, like rattle your teeth out. I could see this job being a potential liability and a hassle for you.

I've never forged mine, and don't really bother with much of a cutting edge on them. I mainly work out dents and dings with a side grinder while maintaining the balance. It cuts just fine.

I'd recommend to sharpen them with an angle grinder or other grinder. They don't need tempering, they take a beating, so they need to be tough, not hard.

All I ever do is just lay under it with a 4 1/2" grinder and touch them up when the need arises, which really isn't very often even with moderate use.

welder19

I'd recommend to sharpen them with an angle grinder or other grinder. They don't need tempering, they take a beating, so they need to be tough, not hard.

All I have ever done was grind brush hog blades and kept the heat down. If it is an actual brush hog it doesn't have to be sharp like a finishing mower. I draw the old style plow shears and hard surface them, that might work on some of the old brush hogs. If they get to that point we buy new blades.

I mowed Federal levees on the Missouri river, 4 miles 4 passes a side 2 sides, (do the math for acreage) with a 20' Bush Hog brand rotary mower.I hammered my blades for 20 years, by hand. heat to yellow , strike for a 20 degree angle, I had a holding jig made out of 6" X 6" X 24" mild steel with 2 c-clamp vice grips bolted to it, and the whole thing bolted to a 6 cyl. ford block. I used an 18 lb sledge. NEVER harden or fast cool.In cold weather I put them in dry wood ashes to slowly cool. Hammered blades cut three times longer. And last till the bolt holes elongate. I did this for my own machine, not for hire. In todays litigious society I don't think I would sell that work.

I sharpen brush blades for a contractor. It is a large hydraulic motor-driven attachment on a skid steer loader.
I use a makita 5" sander. I use 80 grit to shape the blade and 120 to put an edge on. I use a steep angle about 30-35 degrees to give the edge a fighting chance.

i have worked as a fleet equipment tech for 30 years and would advise not to sharpen these blades the sand we have here in florida eats the blades pretty bad,if you sharpen a worn blade you risk damage to the bearings in gearbox its called balance you grind off metal you change balance (take a blade off your ceiling fan and see what happens) why not change the blades its a lot cheaper than bearings and gearbox repairs and other peoples body parts

Thanks guys. I've decided to turn down any request to do this. A set of blades cost about $60 shipped so it's cheaper for them to buy them than it is for me to get sued!! Besides, who owns a tractor and hasn't invested in a grinder? Thanks for the info!