Reheat treating a folder blade/s35vn

rodriguez7

rodriguez7

Gila wilderness knife works
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Feb 1, 2009
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So, I have a hinderer Bowie in s35, that tested really low rc, so I’m wanting to reheat treat it. Looking for 60-61 rc. Sadly it tested out around 57rc. Disappointing. The heat treat I think I have down, 1950 aus, x40 minute soak, plate quench, cryo overnight, triple temper around 400. My main concern is the press fit thumb studs. I’m wondering if I’ll have a fracture on the blade, or if the actual thumb studs will fracture. Anyone have any ideas? Thanks.
 
I'd get those thumb studs out so you can plate-quench it, no?
40min soak sounds excessive to me, but maybe necessary for already-hardened?

Yeah, 57Rc is really low for S35VN, especially in a folder.
 
How are you going to plate quench a knife that has the bevels finished? The Crucible data sheet says you can do an interrupted oil quench down to 1000 degrees and then plate quench but, I still think that is going to lead to a soft edge and probably warpage. Additionally, S35VN does not need 40 minutes at temp; I use 20.

57 might be a little low for S35VN but, it is useable. I have a feeling it won't be a useable knife after you re-heat treat it.

Bob
Edited to add: If this is a folder (I'm not up on Hinderer knives but, I thought their bowie was a fixed blade), you can forget it. Heat makes metal move. You will disrupt your pivot, stop points and your lockup...and, as you mention probably the thumbstud. It makes far more sense to just reblade it and set the original blade aside so you could return it to stock later.
 
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Rc57 was considered high for a commercial folder for nearly a century. It is only recently that people want folders in the Rc 60 range. You will likely ruin the blade if you attempt to re-do the HT. For one, it won't be the same side and thickness after HT and clean up.
 
I think Bob's suggestion is spot on to Reblade makes more sense. Commercial knives often come in lower RC than expected which cuts down on warranty claims for high RC snapped blades.
 
My main concern is warping so it may not be centered after the ht.
 
Yeah, I have to agree about starting fresh. You'll have exactly all of the same problems, but with more material to work with and you won't have wrecked the original part.
 
Normally factory folders are ran a tad soft. But the spiderco farid K2 In CPM10V is quite hard. I’m not sure you could get much more performance out of it.
 
Bob Ohlemann said:
Absolutely. It makes no sense to plate quench an air hardening steel if you can't get full contact with the surface.

Bob
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Thanks ! Make sense ... thin edge have no contact with plate +will draw heat from thick spine all time and will cool down last ........ + you can check hardness where it matters.....on edge . But most knifemaker here HT stainless with bevel already grinded , almost to final thickness ...............at least that is what I read here as suggestion .
 
Natlek said:
Thanks ! Make sense ... thin edge have no contact with plate +will draw heat from thick spine all time and will cool down last ........ + you can check hardness where it matters.....on edge . But most knifemaker here HT stainless with bevel already grinded , almost to final thickness ...............at least that is what I read here as suggestion .
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The trend I am seeing is more and more makers grinding hard.
 
bmilleker said:
The trend I am seeing is more and more makers grinding hard.
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We rarely get blades that are ground. And when thy are ground it’s usually just a short edge bevel that knocks the corner down.
 
On small blades I grind post heat treat, but on large fighters and Bowies made in 3v or Z finit I take it to almost a finished grind as do many other makers.
 
AVigil said:
On small blades I grind post heat treat, but on large fighters and Bowies made in 3v or Z finit I take it to almost a finished grind as do many other makers.
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This is what I’ve been doing, and I have had no problems. I grind to almost finish, because when plate quenching, the heat get sucked out of the thin edge anyway. So it makes no difference, and fully hardens anyway. But thanks everyone. I guess I’ll avoid trying it, and just stick with what I have.
 
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