spring steel

D

dunk

Joined
Jul 27, 1999
Messages
4
How do you work and heat treat spring steel(from cars)?I thought I would try it because it is not that ease to find 44Oc ss or such steels where I live in Fairbanks Alaska.

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[This message has been edited by dunk (edited 09 September 1999).]
 

The springs in cars are(or at least were) made of 5160, which is a high carbon steel that is quenched in oil or water(my preference is oil) The quenching temp. is approx. 1450 deg. or non-magnetic, temper it at 400 for an hour. It is a little bit tougher to grind than 01. Hope this helps.

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KSwinamer
 
I’m not a knifemaker but just ordered a khukuri, which is also forged from a recycled leaf spring, 5160 -- so this is just for my own curiosity. Kisu, Dunk, or others, could you give me some sense of its “values” or characteristics for a knife -- for example, what is its ideal RC and why, how well does it hold an edge relative to other carbon steels (O1, 1084, maybe A2, etc), and what kind/size blade would it be best suited for?

(Also, again, I’m not a knifemaker, but my understanding is that 5160 is technically a “medium-carbon” steel, no? .45-.60?)

Any feedback would be great -- thanks and regards,
Glen
 
I agree with Kisu except I would draw it 2 more times at 400 for an hour. I always do a triple draw on my blades and get better results by doing it.
Ravenclaw
 

Storyville, it is a medium carbon steel, but I havn't seen it affect the performance of it in comparison to 01 etc, the main quality of 5160 is pure toughness, it's probably one of the toughest steels I've used for my knives. I would personally recommend it for medium and larger blades. Thank you, btw, Ravenclaw, I did neglect to mention multiple draws. So, I think, storyville, that you will have an excellent knife in that 5160 khukuri
smile.gif
P.S. you can easily get "hamons" or temperlines with 5160.

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KSwinamer
 
A good temper for this type of knife is 56-58 rc IMHO for chopping and bigger knives. This makes the steel more forgiving and flex more. The 5160 spring steel will serve you well if heat treated properly

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Web Site At www.infinet.com/~browzer/bldesmth.html
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Just to throw confusion into the mix, I recently asked two spring shops what steel they use. One uses 4140 and the other uses 1040 and 1045. Now, these guys concentrate on replacement springs for trucks, so maybe that's the difference.
Bob
 
Thanks all for the education -- and interesting “confusion” too, Bob! (Who knows, maybe some day I’ll start hammering on a leaf spring and end up w/a little more than just a flatter leaf spring!)

FYI -- anecdotal rather than “verified” -- it’s been noted somewhere that the springs stls for the better-made khukuris are taken from junked Mercedes’. I have no idea what real difference that might make; but regardless, their edge-holding, toughness, and general durability in reliable tests has shown to be surprisingly excellent.

Or rather, surprising to someone like me who doesn’t work this stuff, but just based on the little I’ve learned about the heat-treating resources and technology available in semi-urban/rural Nepal, and also since the recycled stls presumably spit out their carbides twice over, no? (It would be interesting to hear from Dunk again, after he gets a chance to work w/his leaf springs...)

Then again, maybe I just read too much... Thanks again, all --

Glen
 
The best way that I have found to treat old
car springs is to take the chunk that I want
to make into a knife and heat it to critical ( and don't worry about temp. because most
pieces of old springs will go critical at different temps.---use a magnet to tell when
it goes non-magnetic (critical))
then put it into some sort of fire proof insulation and let it cool down very slowly.
Then forge or if you can't forge anneal it
another time. If you forge heat to critical
at the end of forgeing and let air cool then
anneal twice. Hardening should be done at
critical (non-magnetic) and if you can quench
1/3 to 1/2 up from the cutting edge in heavy
mineral oil or Conoco pale parifin quenching
oil if not point down quench the whole thing.
Repeat process twice letting the blade cool
to room temp. between process. I heated the oil up to about 165 deg. before quenching Then temp.
for 1 hour at 350 deg. take out and let cool
to room temp. then repeat. Before hardening
leave about 3/32 of an inch on the cutting
edge it will protect the carbon from burning
on the edge. If you can find someone that
has a liquid nitrogen tank and will let you
put your blade in after final grind for about
an hour or two then temper again at 340 deg.
you should have a very tough knife that will
also hold a very good edge. The higher tempering temps. will make your knife softer
and more flexable but will hurt your edge
holding capability. I've treated knives this
same way and have been able to put them in a
vise and bend them past 90 deg. and then back
the other way past 90 deg and not have them
break so what is the sense in making them
softer???? I've also chopped through hard
Oak and not had them chip.........

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http://www.imt.net/~goshawk
Don't walk in tradition just because it feels good!!!!!
Romans 10:9,10
Hebrews 4:12-16
Psalm 91



[This message has been edited by goshawk (edited 11 September 1999).]
 
I`m currently using a method very similar to Goshawk`s and I`ve had really good results with it. However I have to admit that I`ve had good results with auto spring steels and much simpler methods as well. My first knives were made from Pontiac leafsprings and hardened by heating them with an oxy/ acetelene torch,checking for critical temp with a magnet and edge quenching (single) in motor oil. I then tempered them at 400 degrees for about an hour,twice. These knives hold an edge very well without chipping or distorting. One monster bowie (18" OAL)I made this way choppped and split firewood for a group of 4 campers for 3 weeks without being sharpened and was still had a usable edge when it returned. This was certainly not due to my fabulous heat treating! I believe this type of steel is probably just very forgiving. FWIW the truck spring shop I currently get my annealed stock from says theirs are 5160 but I have no idea what the Pontiac springs were. I have found this type of steel to be a little stuborn to work at times though. Even after annealing it most of my files will hardly touch it and it seems to be a little harder on belts than say 01. Marcus
 
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