Quality of lawn mower blade?

[paulc]

Anyone know if it is likely the steel in a worn out toro mower blade could be turned into a descent knife blade?

Thanks, Paul

[Morgan]

Only way to know is to cut a few small pieces off the LM blade and test them. Some are hardenable to the degree that I want a knife to be and some aren’t. If an oil quench don’t get you there try a salt water quench with as much salt dissolves in the water as it will take. If that don’t work, I’d make something else with it. I’ve had JD blades that wouldn’t fully skate the file after quench but you could tell they were harder and you could beat the fool out of the piece in a vice and not break or bend it. I think it’s a crap shoot what you get.

[KHalverson]

a few years ago i went thru the 3  5 gallon buckets of them  that i'd collected over the years.
i only found 4 worth saving for knives.
although some would work for froes or tomahawks.
its a crap shoot.

[paulc]

Dispite lurking on this board for years I really still don't understand the basics of forging.....how do I invest the least amount of very limited time to determine if these are worth investing more time....

Thanks, Paul

[Gimlis Ghost]

I have a Swedish steel lawn mower blade I retired after heating, bending and hammering back into original shape about five times.
When the city revamped the sewer connections they broke up several feet of old pipe and instead of disposing of it they just left the chunks laying in the grass. I bent the blade double several times. Luckily the impacts didn't shear the shaft key.

Anyway this type blade is thinner than you'd expect and comes with a wavy shape that is part of its mulching system. There's no side discharge with that style blade so its safer. The blades are spring tempered to give without breaking and normally spring back into shape.
The steel is definitely tough as it comes.

I have a dagger I made from a section of chainsaw bar, also of Swedish steel. This was an old school bar, milled from a solid plate with the chain groove milled in. I got two old ones that were discarded because the side of the grooves had worn away after decades of hard use.
The steel is very tough and springy and takes a fine edge and needle tip without having been re heat treated. Not sure how well it would hold its edge since I haven't used it for cutting.

I've planned to make a couple more knives from this steel, hunting/outdoor style single edged clip points, but haven't gotten around to it. When I do I'll experiment with hardening the edges.
I figure I have enough left for several knives and possibly a short sword or chopping tool.

Speaking of chopping tools I have a old chopper that is probably at least a century old, probably close to two centuries. Its a short squared off tip chopper my dad used when farming as a lad during the great depression. The handle, which is probably original is the toughest piece of wood I've ever come across.

[Pat B]

I made a few knives a couple of years ago from lawn edger blades I got from Lowes. I got 2 knives from each blade. I've often wondered about lawn mower blades.

[Morgan]

Dispite lurking on this board for years I really still don't understand the basics of forging.....how do I invest the least amount of very limited time to determine if these are worth investing more time....

Thanks, Paul

With your cutoff wheel, cut a couple or three pieces 1/2” x whatever the width of the blade is. Heat to a little past non magnetic and quench in salt water. If it skates a sharp file you can harden it. Then try a quench in canola oil or the like. If it still skates a file, you can use a quench slower and less violent than salt water. From there you have to experiment with temper temperatures and times.

[Don W]

Dispite lurking on this board for years I really still don't understand the basics of forging.....how do I invest the least amount of very limited time to determine if these are worth investing more time....

Thanks, Paul

You could always go ahead and make a knife blade. Harden it Like Morgan mentioned. If it fails, turn it into a nice letter opener. The nice thing about heat treating, if it fails once, just try again.

[KHalverson]

Dispite lurking on this board for years I really still don't understand the basics of forging.....how do I invest the least amount of very limited time to determine if these are worth investing more time....

Thanks, Paul

there are always other options.
ima pull an old thread back up.
dont know if yoy have already seen this.
Kevin

[Mesophilic]

You can also try a snap test.  I'm mentioning it because some beginners reading along might not be sure what a skating file should feel and sound like.

Cut a strip of steel a couple inches long.  Heat treat it but don't temper.  Clamp in a vice and give it a whack with a hammer.  If it bends...not going to work as cutlery.  It should snap or shatter at full hardness.

It also gives you a chance to look at the grain.  When it snaps, you want a creamy silver color, like a texture of 600 grit or better sandpaper.  If you have large grains that look 50 grit, you'll want to refine your soak time and temperature, maybe take a look at your quench as well.

[Morgan]

You can also try a snap test.  I'm mentioning it because some beginners reading along might not be sure what a skating file should feel and sound like.

Cut a strip of steel a couple inches long.  Heat treat it but don't temper.  Clamp in a vice and give it a whack with a hammer.  If it bends...not going to work as cutlery.  It should snap or shatter at full hardness.

It also gives you a chance to look at the grain.  When it snaps, you want a creamy silver color, like a texture of 600 grit or better sandpaper.  If you have large grains that look 50 grit, you'll want to refine your soak time and temperature, maybe take a look at your quench as well.

Good advice.