Truck spring steel and file steel...

[BruiseLeee]

After seeing the Reti in the UBBB section today I'm wondering...

How does steel from a file and steel from truck springs compare? Are they basically the same, and at one point the file is hardened to a higher RC?

Another khuk site says that a blade made from railroad track produces a harder and more durable edge.

Is this true? Perhaps they add some goop into railway track steel to keep it from rusting as quickly as truck springs. More chromium perhaps makes a harder steel therefore a more durable edge.

Or can you just temper any of the steels to the same hardness and have the same edge retention?

I gots to know.

 

[etp777]

Different steels will have different edge retention even at the same hardness, depending o their wear resistance. As an extreme, you can look at the cobalt alloys(which aren't really steel). Stellite Unimet has a HRC in the 30s, but is incredibly wear resistant and will hold an edge for a long time(as long as it's not too thin nad chips).

Current files tend to be W1, or older ones are W2. Truck springs will be 5160, or possibly 1095. with the exception of the 5160, these aren't all that much difference. Compositions:

W1 W2 1095 5160
Carbon 1.0 1.0 .95 .60
Manganese .35 .35 .40 .80
Silicon .30 .30 0 0
Chromium 0 0 0 .80
Nickel 0 0 0 0
Molybdenum 0 0 0 0
Vanadium 0 .20 0 0
Tungsten 0 0 0 0
Cobalt 0 0 0 0



As you can see, not a HUGE difference between any of them. the Files will have a bit higher carbon, and in theory then can get a bit harder, but also a bit more prone to corrosion.

 

[Ferrous Wheel]

and add that it is the annealing and tempering that really makes the source steel behave as you'd expect the khuk to. I think I read about Sarge and Pen making their knives from files and doing some blowtorch heat treats...

 

[Rusty]

The kamis seem to know what works, and that's enough for me.

 

[arty]

From what I have read, 5160 is a very tough steel that is used for larger blades. Swordsmiths like it for this application.
The other steels have a higher carbon content, and could be more brittle - but that depends on how they are hardened and tempered. Some bladesmiths do not like to use the very high carbon steels for blades that are longer than 12" or so.

 

[Daniel Koster]

A very similar question was just asked over in ShopTalk...

Tool Steel vs. Truck Spring

Over there it was O-1 vs. 5160, here it's W2 vs. 5160.



From Bob Engnath's website:

W-1, W-2, and the series of 10-- steels from 1045 through 1095 are the ultimate in simplicity and very shallow hardening so they may be used to make a selectively hardened edge as one sees on old Japanese swords. Toughness is outstanding, with these alloys being used for grader blade edges, truck springs and files. Uses up grinding belts at quite a rapid rate. Edges are acceptable with 1045, good with 1060, nice with 1084, and excellent with 1095, W-1 or W-2. Those last two are often referred to as O-F, old file. It is very easy to get the higher carbon end of this series way too hard to make a good knife.

5160 is a common spring steel, basically 1060 with one per-cent of chromium added to make it deep hardening. (It may still be selectively drawn with a softer back, if desired.) An excellent steel for swords, or any other blade that will have to take some battering. The choice of Jim Hrisoulas who makes some of the finest working swords in the business. Long blades are best around the mid 50's on the Rockwell scale, while small, working blades can be put into service at a full 60 RC. Forged blades with a well packed edge seem to cut forever! Rough on grinding belts. Jokingly called O-C-S, old chevy spring.

 

[Daniel Koster]

1. How does steel from a file and steel from truck springs compare? Are they basically the same, and at one point the file is hardened to a higher RC?

5160 is usually tempered to 55-58, while W-2 tempers to 60-61

2. Another khuk site says that a blade made from railroad track produces a harder and more durable edge.

I pity the guy out there banging on the railroad track....yikes! Hope his hearing is ok...

3. Is this true? Perhaps they add some goop into railway track steel to keep it from rusting as quickly as truck springs. More chromium perhaps makes a harder steel therefore a more durable edge.

It all depends on the Heat Treat - that's what sets the hardness. I'd say if the kamis have been heat treating all these years - chances are, they know how hard to temper it. (doesn't mean it's a perfect process...just the right process given the circumstances)

4. Or can you just temper any of the steels to the same hardness and have the same edge retention?

Nope.