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Lawn mower blade as tool steel?

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Forum topic by jtriggs posted 307 days ago 1698 views 0 times favorited 12 replies Add to Favorites Watch
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jtriggs

57 posts in 2322 days


307 days ago

Topic tags/keywords: tool tool steel lawn mower blade

I’ve heard of using old reciprocating saw blades as a source of thin tool steel. What would be the result if you used an old lawn mowing blade for a thicker profile? It would seem to be a cheap alternative to going and buying tool steel somewhere.

Thanks for any advice.
Jon


12 replies so far

View scotsman9's profile

scotsman9

134 posts in 394 days


#1 posted 307 days ago

Lawn mower blades by standard are made of extremely soft steel. They have to bend and dent when hitting rocks and other hard debris. If they were made of tool grade steels, they would shatter and become missiles. So, manufacturers make them with soft soft soft steel.

I’m not quiet certain, but I think the Feds of an allowable hardness for lawn mower blades.

???

-- Just a man and his opinion.

View Nomad62's profile

Nomad62

669 posts in 1463 days


#2 posted 307 days ago

There’re just not the same thing, kind of like brass vs bronze; there are differing amounts of carbon (in the steel) in each, and they are made and formed differently. You could never get the soft metal of a mower blade to do the work of tool or stainless steel.

-- Power tools put us ahead of the monkeys

View Buckethead's profile

Buckethead

770 posts in 374 days


#3 posted 307 days ago

I’ve heard the Egyptian Great Pyramid’s stones were cut partly using copper tools, but then again, I’ve also heard they were built by aliens.

So as long as an alien is wielding the tool made from the softer steel, it should be fine. :-)

-- Hi. My name is bucket head and I'm a recovering framing carpenter.

View crank49's profile

crank49

3249 posts in 1476 days


#4 posted 307 days ago

My former employer makes cast alloy iron with a hardness that surpasses most tool steel, Rc 62 to 65 but is used in blow bars and hammers for hammer mills. These wear parts are designed for extreme hardness and impact resistance. Hardness does not directly relate to toughness and impact resistance.

Also, generally stainless steel is softer than even mild steel, with the exception of the 400 series. And the 400 series, although it can be hardened to Rc 60 or so, is a nightmare to sharpen.

Anyway, the blades of a rotary mower are designed for toughness and not necessarily hardness, as was already stated. But, it is possible they could be hardened by heat treating.

-- Michael :-{| Diapers and politicians both need to be changed often; and for the same reason.

View bondogaposis's profile

bondogaposis

2239 posts in 856 days


#5 posted 307 days ago

It depends what you want to make with it. A similar sized bar of O1 tool steel from Mcmaster Carr might cost double what you could buy a lawn mower blade for, but it will be all useable, with out all of the bends etc. The nice thing about working w/ tool steel is that you can do all of the shaping, drilling, etc. before you harden it. Where as if you have ever tried to drill a hole in reciprocating saw blade you know what I am talking about, impossible.

-- Bondo Gaposis

View waho6o9's profile (online now)

waho6o9

4456 posts in 1082 days


#6 posted 307 days ago

http://www.harborfreight.com/5-piece-m2-high-speed-steel-mini-tool-bits-for-metalworking-lathes-40641.html

Here’s a good alternative for a good quality HSS that’s cost effective.

View Jim Finn's profile

Jim Finn

1508 posts in 1427 days


#7 posted 307 days ago

We used top use old auto leaf springs to make tools with.

-- In God We Trust

View jtriggs's profile

jtriggs

57 posts in 2322 days


#8 posted 307 days ago

Thanks everyone for the swift replies. You’re right of course, I’ve seen enough dented blades on a mower to know that is softer than tool steel should be. Thanks for the other suggestions.

This is the smartest place on the web.
Jon

View Tim Scoville's profile

Tim Scoville

96 posts in 1840 days


#9 posted 307 days ago

During my trips to Asia, it was common to see lathe tools made from steel files as these are normally hardened and keep an edge pretty well.

-- Tim S, WA

View casual1carpenter's profile

casual1carpenter

353 posts in 981 days


#10 posted 307 days ago

Jim, we have used leaf springs also, but you can not be real aggressive with grinding and shaping, as they can become brittle. Also without real information and actual material specifications you would need to be mindful of things not blowing apart before your very eyes. Some how I’m thinking lathe tools and a brittle type failure here. I came with two eyes and other various body parts and would really like to keep them.

View Loren's profile

Loren

6774 posts in 2153 days


#11 posted 307 days ago

I know swordmakers make swords from them. I don’t
know if they hold an edge though… these days most
handmade swords are made for show and aren’t
sharpened for safety reasons.

View Jim Baldwin's profile

Jim Baldwin

48 posts in 863 days


#12 posted 307 days ago

As a rule, if you can file the metal than it’s soft steel (lawnmower blades are sharpened with a file). If the file slides across without removing material, than it’s hard. Of course soft steel can be hardened by heating and quenching (machine shop 101). In general all old handsaws, circular, band and hack saw blades are good tool steel as well as old files. Gardening tools are not hard with the exception of the machete which is good spring steel. Don’t overlook old putty knives and scrapers which are also hard.

Do I have to say “never use scrap steel as knives, in powered rotating equipment? (homemade junk kills people).

-- Jim Baldwin/18th Century Handrail http://handrailer.com/

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