Lawnmower blade knife

The blade metal is too soft to work as a knife without hardening. You'd need to temper the steel if you want it to hold an edge.

"HOW?" there's already enough information available on how to heat treat knives, here, online and in books, look it up.
 
In a word, no. It can be done but it requires so much work that you are much better off buying 1084 barstock. They are also something like 1045. They don't hold an edge very well.
 
OverUseOfMachetes said:
Cool. I habe heard of a tempering where they heat it up REALLY hot then dunk it in ice water. True?
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NO! What you are talking about is hardening which is entirely different. If you are really set on doing it, here are the steps you should follow:
1- Using a cutoff wheel, cut it into managable pieces.
2- Heat to red hot with a torch and stash in vermiculite over night
3- File, drill, and sand until you have a good knife shape
4- Heat to slightly above magnetic and quench in brine(1 pound of salt per gallon of water)
5- Temper in a kitchen oven set to 400 degrees twice for 1 hour each
6- Hand sand the bevels, flats, and edges clean and polished
7- Make handle scales

This is extremely over simplified for the sake of consiceness.
Go over to Shoptalk and read the stickies.
 
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OverUseOfMachetes said:
Cool. I habe heard of a tempering where they heat it up REALLY hot then dunk it in ice water. True?
Click to expand...

If your gonna give knife making a shot, go over to the knife makers Q&A there very helpful with this kind of stuff....also give the sticky's at the top of the page a skim to see if the answer is already there....also the answer the heat treat question yes and no som steels need to be quenched in water but most in preheated oil..there's a lot of tutorials on the wb with specifics.

Also if you want a good place to buy steel check out New Jersey steel baron (Aldo)

Hope it helps!

-niner
 
There is no standard formulation for lawn mower blade steel; no way of knowing what it actually is.

Likely a low carbon steel designed for toughness.
 
I would think it would be too soft, as a lawnmower blade bends, collapses and otherwise gives when struck at high speed. Otherwise it would shatter, which would not be good, and wind up injuring someone. Can we say lawsuit? Better to try an old file or rasp.

Blessings,

Omar
 
I had previously bought steel from Usaknifemaker, but checked out New jersey steel baron again today. Wow are his prices goooood. I bought a piece of 1084fg 12x1.5x.25 and it was 9 bucks at usaknifemaker. Over at aldo's there is 48x1.5x1/8 for 14 bucks.


I would also recommend buying some steel. It's cheap, and then you don't have to worry about heat treatment for some mystery metal(of which alot of cheap blades are nowadays). I'd stick with something like 1084 and just follow the standard heat treat for that.
 
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I know this is a couple months old at this point, but after reading this thread and seeing it asked so often I wanted to give it a try. My father in-law owns a lawn mowing business and I have a unlimited supply old old blades. Each blade seems to have a different grade of steel even with the same manufacture, probably because they use recycled steel and their recipe is not very consistent. That being said I spark tested until I found the best one and cut it in half. Most modern lawn mower blades are made to mulch and have humps built in during stamping and a curve plus a upturned wing, so it has to be hammered straight. Due to the humps and there is a slight variance in thickness through out the blade. I did not anneal since I had to get it red hot to hammer and once it was "straight" enough I allowed it to cool in the coals over night. I followed the heat treating as I would with a 1080ish steel. It holds a edge OK, about what I see with a cheap Gerber drop point which I think is a 440a stainless. With all the coal I used to hammer it, plus time and the end result is a knife I could of bought for about $16. One plus side is I'm not afraid to abuse this knife but I doubt I would make another.
 
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