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Oyster Knife

Thoughts on optimum hardness?

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#1 Ben Noffsinger

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Posted 22 December 2013 - 11:22 AM

Hey Gents,

 

I am making a oyster shucking knife for a guy and I'm considering how far to temper the blade back.  I know I don't want it as hard as my kitchen knives, but I don't want it to deform under usage.  I am using what I believe to be 5160 (piece of coil spring).  I am thinking somewhere around 50-54 RHC?  Any advice or thoughts would be much appreciated.

 

Ben



#2 shawn patterson

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Posted 22 December 2013 - 11:39 AM

My guess would be flexible over hardness but, I'm guessing.

#3 Tyler Miller

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Posted 22 December 2013 - 01:02 PM

I would think 5160 with a spring temper would give it all the performance you need.  Maybe something slightly more stain resistant due to their brininess?



#4 Stephen Olivo

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Posted 22 December 2013 - 02:22 PM

Forge one and use it without anything but normalizing cycles.  This may give you the springiness you need.  Then if it doesn't hold up/isn't like a fillet knife springy then try hardening in oil temper to 425 for at least an hour.  Then put it into use again.  repeat adnausium changing variables till you get what you want.  With unknown steels its hard to give you specifics but I have worked with steels around this kind of found type and I find cooking oil quench from bright red after 3 normalizing cycles and immediate tempering cycle at between 400 to 450 gives me a pretty good tool.  You may need to draw the temper more than that but then all you have to do is repeat the tempering in the oven at a slightly higher temp and then test it again to see if it is as springy while still hard enough for you.  If at all possible it is better to work with known steels when making things for someone else.  Just more consistent results.  


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