[TheForge] lawnmower blades

[David E. Smucker]

How "old" is the blade?  Today most blades are being manufactured in 
China -- China blade manufactures say they are spring steel with a hardness 
in the low to mid 40's Rockwell C.  -- Not mild steel.  Older American 
blades also would be some type of lower cost spring steel.  Roger's 1060 is 
not a bad guess, some might even been 1045, as it was a very common steel. 
Ultra heavy duty blades such as used on bush hogs 1/2 inch thick by 3 inch 
width are often 5160.

Dave Smucker

----- Original Message ----- 
From: "Bob Brashear" <rjbrash at hutman.net>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Monday, September 17, 2007 5:30 PM
Subject: Re: [TheForge] lawnmower blades


> Roger R Degner wrote:
>> A few years ago had someone at a conference give me a blade blank he said 
>> it
>> was a 10XX and I think 1060 but could be wrong.
>> Draw out a blade into a small cross section.  Heat to nonmagnetic and 
>> quench
>> in water.  Stick this hardened but not tempered piece in the vise with a
>> little sticking out.  Wearing eye protection lightly hit the end sticking
>> out with a hammer.  If it breaks like glass it is high carbon, if it 
>> bends
>> over after repeated blows it is mild steel.
>>
>> You can try this with an oil quench which is not so severe.
>>
>>
>>
>> Roger R Degner
>
> Thanks for the tip, Roger. Very nice. Lawnmowers are shuddering in fear!
>
> Bob
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