[TheForge] Lawnmower blade question

[Dave Smucker]

Wes,  Lots of different steel could find there way into lawn mower blades.  They will not be mild steel.  From the low end it my be similar to 1045 to the high end 5160.  The first 1045, is just a common medium carbon steel,  the second 5160 is a typical high performance spring steel.  Lots of other are also possible.

 

So what to do?  First spark test it to see if you can get a feel for carbon content and look at the color of the spark as well as the star burst.  It is helpful if you have a known steel to compare it to.

 

Next test is to do a test heat-treat.  Heat the blade slowly to just above critical (non-magnetic) and then quench in oil.  Test with a good file -- if it comes up hard then you have a steel made to quench in oil and it has a fair amount of alloy content.  If not hard or not very hard (file bites a little) then it is likely you have a water quenching steel.

 

If that is the case repeat the test and then quench in water rather than oil.  It should come up hard this time.

 

For finished products don't forget to temper.  I like to temper in a oven most of the time at 375 to 400 F unless I just want toughness and then I go higher.  Temper in the oven for 1 to 2 hours.  Or you can color temper.

 

Dave Smucker

Brasstown, NC

but right now in Waterloo, ON (the great white north, but spring is here today)
 
> From: marquart at arlinn-tower.com
> To: theforge at mailman.qth.net
> Date: Thu, 13 May 2010 01:45:08 -0500
> Subject: [TheForge] Lawnmower blade question
> 
> Hi guys, figured I'd ask the collective mind.
> 
> 
> 
> This spring I've tapped into a local source for used lawnmower blades. When
> I asked if they ever had any they said "Oh we get a few. Want us to save
> them for you?"
> 
> 
> 
> I said "Please" and now I've gotten a whole bunch on my hands! (And I'm due
> to go by tomorrow to pick up a bunch more)
> 
> 
> 
> So the questions are these:
> 
> [1] any ideas on what these are made out of? Obviously Steel, I'm just
> wondering what sort. they seem to be pretty tough stuff.
> 
> [2] things I can make out of them? So far I've come up with camp
> knives, garden trowels, and brush knives for projects. 
> 
> 
> 
> Tomorrow after I get home from my 'source' I'm planning on putting together
> a hiller/furrower for the Mantis tiller. That's where I get the blades,
> local rental place where I have that thing worked on.. This time it needed
> a new clutch. easy to replace but that little part is expensive.
> 
> 
> 
> I wanted a Troy built, the wife wanted a Mantis. so that's what we got
> [shrug]. Now I get to keep that little thing up and make attachments for
> it.
> 
> 
> 
> So ideas, advice?
> 
> 
> 
> Wes
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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