What steel type does GEC use for backsprings?

Thank you Mike. Also guys, I don't think 58-60 tangs and 45-48 springs rubbing are as big a deal that you think. Ask any maker.

I will try to get a post written explaining spring temper and how the hardening process works, but I'm going to have to type it on the computer, not my phone.
 
arizonaranchman said:
Yep, makes sense to me. They've got to be substantially similar in hardness or the blade will wear the spring badly over time.
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This is absolutely not the case.


Ok, I guess I'll do it here. It boils down to geometry determines flexibility, hardness determines if metal will snap or take a set (stay bent) once it exceeds the modulous of elasticity.

Filet knives bend because they are super thin, not because they are soft. Back springs bend because of their geometry, but return to their original position because of their hardness.

A blade at 30 will bend them maybe stay bent. The same blade at 64 will bend then snap.
 
Markesharp said:
Blades and backsprings are made from the same steel and heat treated to the same Rc (Rockwell) hardness for most production and custom folders.
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I never knew this. I am guessing this is for issues of wear if the spring were not of the same steel and Rc?
 
knifeswapper said:
With SS blades, they use 410, 420, or 420HC backsprings depending on the thickness. With 1095, they use 1095 backsprings. Both hardened to around 45-47.

They anneal the tang of the blade to about the same as the backspring.

They grab a handful (10 or so) from each batch (100+) that comes back from heat treat and hammer test them.
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I know nothing, but my gut tells me there's no way a 1095 blade at 45 could keep an edge like my GEC's do.

Edit:
Never mjnd, I see what you are saying.
 
Thomas Carey said:
I never knew this. I am guessing this is for issues of wear if the spring were not of the same steel and Rc?
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I realize you posted again later, but I just wanted to make an interesting point. The steel in the spring vs blade absolutely can be different. In fact, I do believe when Schrade was using up parts, there were a few carbon bladed stainless spring knives made. I think it was Schrade anyway.
 
Ats-34, Blades 60-61RC, springs 48-49RC. I've Rced a pretty fair amount of
older slipjoints and many of them were right around that 50Rc Mark for the
blade and the spring. I'm sure it facilitated crinking and such with a lot less
fear of breaking a blade. Plus they were much easier to sharpen. The highest
Rc I got on an old knife was a Pal scout knife at 62 on the blade.
Ken.
 
kc custom said:
Double post.
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Thanks Ken. I have access to an Rc tester and 5 or 6 old knives that I have torn apart for re-hanling. I am going to test the blade, blade tang and back springs on all of them.
I will follow up with the results........It should be intersting.:)
 
Here's what I do, can't talk for factory or other custom makers. I wrap in 002. tin foil spring an blade. put in furnace, after holding around 1200 for 20 minutes run up to what heat IM doing for that particular steel. it's usually around 1850 to 1925 F. After soaking at temp again depends on thickness an type of steel. then take out of oven an air cool for the Stainless I do. Clean scale with sander check for hardness, hopefully around 63 r. Then I put both back in oven again to lower hardness an gain ductility an toughness. After 2 hours take out put in liquid nitrogen, ( overnight ) take out next day. Put back in oven after Checking hardness again. Then after one hour recheck hardness after they cool completely. if around 59 -60 stop , if still 61 or more back in for one more hour. almost always it is 59-60 by now. Next put springs only in furnace an put dial around 1060 check after 10 to 15 minutes take out cool off test for hardness, see where it's now. you want a spring to be between 48 an 52 if higher it will break eventually-if lower then 48 it will gall an not open slick an smooth like it should, an to those who say the spring will wear out first. yes over time but probably not in your life time, especially if you oil it an keep it clean like you should do. You take care of it -it will be there when you need it. Most knife companies keep there spring temper around 47 to 53. I never go below 48 or over 52, I want perfection an the way it is supposed to be made. My two cents worth.
 
Thanks, Joe. That's as good an explanation as I've ever seen.

So don't forget to OIL THE JOINTS guys and gals!
 
Markesharp said:
Blades and backsprings are made from the same steel and heat treated to the same Rc (Rockwell) hardness for most production and custom folders.
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Don't know if there's really much truth in that, to justify a generalization. Prominent exceptions among production makers:

Queen's D2 folders have 420HC backsprings (they confirmed this to me via email, when I asked).
Case's CV knives have stainless (420HC) springs.
At least some of the older Camillus-made Buck 300-series knives had 440A blades and carbon steel springs (I have a 307 like this, with darkly patinated springs).

These are only the ones I'm immediately aware of; I'm assuming there are more, if one were inclined to dig further. I'd bet a lot of the knives using the same steel for both (though at different RC, as pointed out) are coincidental, especially if the blades happen to be in 420HC or 1095.


David
 
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Obsessed with Edges said:
Don't know if there's really much truth in that, to justify a generalization. Prominent exceptions among production makers:

Queen's D2 folders have 420HC backsprings (they confirmed this to me via email, when I asked).
Case's CV knives have stainless (420HC) springs.
At least some of the older Camillus-made Buck 300-series knives had 440A blades and carbon steel springs (I have a 307 like this, with darkly patinated springs).

These are only the ones I'm immediately aware of; I'm assuming there are more, if one were inclined to dig further. I'd bet a lot of the knives using the same steel for both (though at different RC, as pointed out) are coincidental, especially if the blades happen to be in 420HC or 1095.


David
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I was going to raise this point - ref Case's modern production knives having stainless springs. I noticed this very quickly with my Peanut. The springs are def NOT steel, as my blades are taking on a quick patina but the springs are as-new looking.

When did Case switch to SS for the springs on their CV models?
 
I didn't realize that Case's cv knives had stainless springs. This is becoming a very interesting thread!
 
^^^^ I didn't either til I got my Peanut and realized the CV blades were just taking on a nice patina pretty rapidly but the springs = NOTHING! Bright and shiny!
 
This is some very interesting information, thanks to all who have shared!
 
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