my first slipjoint and a question about carbon steel springs

H

HSC ///

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Nov 7, 2012
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so I took a class this weekend and made my first slipjoint, very satisfying indeed and learned alot as always.
The blade and spring are CPM-154

I'm thinking I'd like to (for now) heat treat carbon steel for my springs as I make a few more to learn
I can HT carbon steel in my propane forge.

Can someone assist with the HT guidelines for a carbon steel spring

for the SS , I used 1725 deg for 15 mins, quench between alum flat plates, temper 2x at 400 deg for 1 hour each
I probably could get my forge to hold this temp for 15 mins if I had to,
but nevertheless I'd like to know a carbon steel spring HT cycle

thanks

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Something like 1075/95 I would harden it as you would any blade, but when tempering, draw it back to 45 RC or so based on the temper data for that steel. You don't want to try and vary the hardness with the austentizing temperature.

For 1075 that would be something like 600F temper temp.

Thats a good looking knife :thumbup:
 
While I use a torch to heat treat my springs, my method will work with ovens.
I use 1095 for springs.
Time at temperature is not crucial for pocket knife springs. Simply heat, hold at temperature for a few seconds, and quench in room temperature canola oil.
Temper to steel specs for spring quality. Again, time is not particularly crucial here-temperature is. There is no need for multiple temper cycles on knife springs.

I know this isn't what some "experts" will tell you, but they haven't made thousands of switchblade leaf springs have they? I have and exactly 5 have broken-all from the same piece of steel. The number would be lower, but I couldn't locate which piece of steel was bad!

The springs I make are subject to quite a bit more flex (and use!) than slipjoint springs. When I make backsprings I heat treat exactly the same as kick springs.
 
Do you temper to color with your torch as well Bill?
 
I harden and temper the spring exactly the same as a blade, but then I clean the spring to bare metal, and heat the spring slowly to a uniform blue color. I do this with a piece of 1/4" mild steel plate on top of my propane kitchen stove. I just lay the spring on the plate which acts like a diffuser to make the heat transfer slower and more even. When it is a uniform blue, I quench the spring in water.

Works for me, but I haven't made thousands of them:D

One I did recently carbon steel Damascus of my own bashing.

Darcy

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I've had luck also just past blue--- going into a very flat gray color. Or I just use my Rc tester
and get it around 47-48.
Ken.
 
All my slip joint springs are heat treated with a torch, then tempered with the blade, then heated past blue color with torch. Usually have to heat to a gray color twice to get hardness below 50 Rc. Done hundreds this way in the last 25 years and only a couple broken early on.
 
last night I spring tempered 3 successfully
one key detail I want to add that the steel must be clean and shiny or the colors won't be apparent.
at least it wasn't apparent to me the first test one I did that was not shiny.

also I timed it and it was about 20 seconds to get to that blue color
I did it three times, i got a HRC reading of about 45

thanks
 
HSC /// said:
last night I spring tempered 3 successfully
one key detail I want to add that the steel must be clean and shiny or the colors won't be apparent.
at least it wasn't apparent to me the first test one I did that was not shiny.

also I timed it and it was about 20 seconds to get to that blue color
I did it three times, i got a HRC reading of about 45

thanks
Click to expand...
I feel they should be heated slower & take longer, to make it a bit tougher. It takes me two minutes or so to heat to a blue color.
 
Don Hanson III said:
Yes, I use a propane torch turned down real low.
Click to expand...
so here u go,
here's the first on on my own in black micarta, SS liners, laminated Hitachi white steel that I forged
1095 spring

not perfect, and I messed up the rear tang so the half stop is no good, but many things did go well
and I even sold it :)

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HSC /// said:
so here u go,
here's the first on on my own in black micarta, SS liners, laminated Hitachi white steel that I forged
1095 spring

not perfect, and I messed up the rear tang so the halt stop is no good, but many things did go well
and I even sold it :)
Click to expand...
Looks Really good for a first! My first wasn't good enough to sell. lol
 
very nice!
Tempering is a diffusive process and it does require time to be even.
Shining carbon steel, well cleaned from any oil residues will show more reliably the tempering colors.
Also i ht blade and spring the same at first, but then one thing i do, that makes me feel better, it's to draw to blue (or past blue depending on the steel. i.e: 1070 to blue, W2 to grey) just the flexing part and the pin areas of the spring. I prefer not to draw too much the walk area to prevent wearing.
One more thing to consider. As you have seen there is a general agreement about carbon slippy blades and springs not requiring too much time at temperature since their small dimensions. With good steel microstructure preparation it is true, but for the same reason (thin and small) it is very important to avoid decarburation with all means possible, be it by protection or allowing for decarb removal. Otherwise it will be galled springs and lousy edges.
 
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one thing I'm curious about, those who use carbon steel springs, do you coat them in anything for rust protection?
Camellia oil?

Harbeer
 
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