How hot can a knife get before the heat treat/temper are affected?

S

slurptoss

Joined
Apr 17, 2013
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Let me share a quick story. I bought a Manix 2 in s30v around 2 months ago. I love the knife and have been carrying it everywhere. I would sit it next to my laptop whenever I would peruse the internet, just to have something to fiddle with. I would sometimes set it next to the heat-discharge-fan-port thing on the side of my laptop, because I loved the feeling of gripping the knife when it was nice and warm from the heat that my laptop kicked off. One day im just screwing around and (knowingly) abusing the knife. It holds up fine through some batoning in sub zero weather, and as I go to take a break I stick the tip in a near frozen log. When I looked at the knife later, about 3-4 mm of the tip had bent over at about a 25 degree angle. I was amazed that s30v would bend that much, especially in freezing cold weather. Long story short when going to bend it back the tip snapped off and I ended up having to regrind the tip, no biggie though :) I still love my manix to death and it was in no way the manufacturers fault. My question is, could the reason that it initially bent instead of snapping be because it being heated up by my laptop effected the heat treat? How hot can a knife get before it is affected? Thanks, I look forward to your opinions :D

- Jacob
 
So do you think that the heat treat from the factory somehow left the tip softer, or am I just underestimating s30v's toughness?
 
No,
You bent the tip in the wood and then once it was stressed you broke it trying to straighten it. Neither the laptop or cold weather had anything to do with it.
 
slurptoss said:
So do you think that the heat treat from the factory somehow left the tip softer, or am I just underestimating s30v's toughness?
Click to expand...

Thinner = easier to bend. Harder (Hrc) = more resistant to plastic deformation (taking a set), narrow 'window' wherein the metal may be bent plasticly and not fracture. Softer = less resistant to plastic deformation. Tougher = more resistant to fracture.

It is entirely possible that you bent the tip just enough to make it set without fracturing. As said above, bent it was in a "stressed" state, bending it back was sure to snap it. If the tip had been "soft" I suspect you'd have noticed it dulling often and easily.
 
I wasn't addressing the snapping or blaming spyderco, I was simply wondering why a thick tip of 60 HRC s30v would bend instead of breaking.
 
How thick? 60 Rc doesn't mean it won't set a bend, it just takes more force to get there than a softer piece of the same dimensions, and has a lower threshold whereupon fracture occurs.

There doesn't need to have been a fracture present prior to or after the initial bend.
 
It's a hollow ground manix 2, so the tip was fairly thick. I can't find exact dimensions anywhere sorry :(
 
slurptoss said:
It's a hollow ground manix 2, so the tip was fairly thick. I can't find exact dimensions anywhere sorry :(
Click to expand...

That's alright. I did find this image from marthinus:

photo-20.jpg


Is that how yours look prior to fracture?

Anyway, no the temperatures didn't alter the HT and unless you noticed edge-flattening issues at the tip in other circumstances, i doubt it was soft from spyderco, and 'toughness' usually refers to impact and doesn't really enter into the equation here. I am glad you were able to fix the problem after the fracture, well done :thumbup: Now you know more about the durability of a tip with that geometry.
 
Don't underestimate the toughness of frozen wood. The wetter the wood the tougher it is when frozen.
 
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