Lawn mower blade steel

S

sicilian767

Well-Known Member
So, this is a question to get y'alls input on something I've been getting mixed reviews on, and that's lawn mower blade steel. I've heard some people say it's medium to high carbon steel, other people say it's junk for making knives. My guess is it's a mild steel, like 1055 or around there, but if that's the case then it would make a good machete. I got three old blades, so I was curious if any of y'all knew what kind of steel it is? I've never worked with it before. But if it isn't a medium or high carbon steel, then I'll probably use it to practice making blades on once I get an anvil regardless.
 
The blades make good enough knives. Old chainsaw bar is good too. They're a "mystery" steel but fits the definition of a knife well enough. Throwing some really ballpark figures out, they're usually a medium carbon with possibly other alloying metals engineered for cheapness to fabricate and durability. Edge holding in the designed product is a long ways down the line of what they're built for, but they'll sharpen up and cut well enough. Your 1055 machete is built from the same hardening class of steel as a lot of mass market knives that are "good enough". As for an anvil, those blades should be thin enough you can just remove what's not a knife from them. I'm going to grossly oversimplify here, but if you take them to 1500 degrees or a little past non magnetic with a warm canola oil quench, leave them a little heavier at the edge than you plan on the finished product being to help prevent warping, make sure a file won't bite after the quench so you know you "nailed it" and a 375 2 hour temper, you should be good to go.
 
Wow, sounds great! Looks like a good thing I held on to the blades then. I think I'll make some machetes out of them. And yeah, I love 1055 for machetes. I have a Cold Steel Kukri machete that I've used for going on 6 years, and all the black anti-rust coating has come off from use. Great blade. It can take a real beating, but it just keeps on going. It's my go to, nearly indestructible blade. I can get it razor sharp if I use the Gatco diamond sharpener. Hopefully the lawnmower blades will make an even better machete though.
 
Its funny just had that conversation with a buddy who owns a true value here in Stoughton, he told me if you can get a pre 2000 blade they were around 1040 to 1055 depending on the company but they were breaking off if they hit something. So he was told almost all have gone to 1020. So I tend not to use them at all myself,but if you are going to test the heat treat first, and like frank said if it skates a file it should at least be a good machete. jm2cents
 
Most are a low to medium carbon, and not really designed to hold an edge (you can "cut" grass with anything), but rather to bend/roll/deform when they hit a rock or a tree stump.

That said, I've still been known by polish my mower blades to a hair popping, convexed edge before... :) It's probably no longer hair popping after the first 5 minutes, but it's something to do on a rainy day.
 
I wonder if one of our members with Rockwell tester and mower could do us a favor, just for informational purposes, and yank their blade off and give it a test. I'm curious, but not curious enough to take one of my blades down to the machine shop sort of thing.
 
Hmm, interesting. Part of what peaked my interest in this was this video, in which he said the steel was high carbon (which I highly doubt is true) but I was impressed with how easily the steel broke off rather than bent after he hammered off the tip at 5:05 in the video: http://www.youtube.com/watch?v=rJoR3uPJTmY

I'm gonna see if I can invest in a rockwell tester soon, and test out the steel on that. I tested the steel with a file, and I noticed it was much more resistant to the file than a piece of steel I knew to be mild was. So I'm thinking lawn mower blades might make an okay knife, and a decent machete.
 
Ya gotta think "Liability" and "Future Sales" with lawnmower blades.

As a result, don't expect much at all from mower blades. If you have the time to forge them flat, then go through all the riga-ma-roll of trying to heat treat them, then you will probably wind up with a blade that holds an edge about as long as a "Mower Blade".

I would love to make a mower blade from 1084 or O-1 if I could figure out how to get those "High-Lift" curves into it, and ensure it would be balanced. But then again, I would probably leave it too hard and it would hit a rock, break a chunk off, sling it through the neighbor's picture window and kill his mother-in-law. :)

Robert
 
Robert Dark said:
Ya gotta think "Liability" and "Future Sales" with lawnmower blades.

As a result, don't expect much at all from mower blades. If you have the time to forge them flat, then go through all the riga-ma-roll of trying to heat treat them, then you will probably wind up with a blade that holds an edge about as long as a "Mower Blade".

I would love to make a mower blade from 1084 or O-1 if I could figure out how to get those "High-Lift" curves into it, and ensure it would be balanced. But then again, I would probably leave it too hard and it would hit a rock, break a chunk off, sling it through the neighbor's picture window and kill his mother-in-law. :)

Robert
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HAHAHAHA.... that's too funny. So tell the truth Robert did your neighbor put you up to this, in order to "take care" of his mother in law..... !!
 
ARCustomKnives said:
That said, I've still been known by polish my mower blades to a hair popping, convexed edge before... :) It's probably no longer hair popping after the first 5 minutes, but it's something to do on a rainy day.
Click to expand...

Heh, I just spent a few minutes doing just that, I don't think they'd ever been sharpened before...:biggrin:

Interestingly enough, it sparked about the same as 1080, but I think it is safe to assume all manufacturers do not necessarily use the same steel, so all lawnmower blades should not be assumed to be equal. I've heard the same information Franklin gave, too, but these are definitely not 1020 and were bought just last year. If you want to make a good knife without having to guess at heat-treatment, buy your steel from a reputable dealer. If you want a challenge, go for the lawnmower blade.... just be sure if you sell the blade to let the customer know the source of the steel.
 
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