Thread: Knife making!

Impossible to say. You are making a first of something. There is always trial and error involved, figuring out how to use the tools best, figuring out how to fit a handle to a blade, etc. Depending on how much knowledge and experience you have to build on, and which tools you have at your disposal, it could take you anywhere from a day to a month.

With the tools the shop has the size of the blade makes little difference in how long it takes to finish. With that said, I watched a fellow get a knife hammered out of a railroad spike, shaped, and quenched in one 6 hour session. It was his first time working at the forge. All he had left to do was temper it a few hours in his oven, and do the final clean up sanding.

I would say 3 to 5 days working time would suffice unless you've got little to no experience shaping materials or never have a large chunk of time that can be devoted to it. A day or 2 to shape the knife and get it quenched, a day to anneal it, and however long it takes you to clean off the remaining scale, polish it suitably, and put an edge on it.

Actually railroad spikes contain so little carbon that the quenching and tempering is pointless.

Mike blue researched it and eventually tracked down an engineer from a company that made them. Even the 'high carbon ' ones contain only .2 % which is perfect for spikes that you don't want to risk fatigue hardening.

You'll find plenty of people to argue about this but the fact is that the amount of carbon is so low it will not harden properly

Well, that was just anecdotal to show how fast you can get a quick no frills simple blade knocked out. There's a reason that I've only used quality knife and tool steels for my projects so far. It didn't seem to me like they would be very high in carbon.

I did the basic research into this question a long time ago (first internet discussion in 2003). The reference you need to complete your study is the American Railroad Engineering Association (in italics): I quote...(the important bits are in Bold)


AREMA Manual for Railway Engineering 5-2-5

Section 2.2 SPECIFICATIONS FOR HIGH-CARBON STEEL TRACK SPIKES1 (1968)

2.2.1 SCOPE (1968)

a. These specifications cover high-carbon steel track spikes.

b. A supplementary requirement, Article 2.2.14, of an optional nature is provided. It shall apply only when

specified by the purchaser.

2.2.2 PROCESS (1968)

The steel shall be made by one or more of the following processes: open-hearth, acid-bessemer, electric-furnace, basic-oxygen.

2.2.3 CHEMICAL COMPOSITION (1968)

The steel shall conform to the following requirements as to chemical composition:

Carbon, min, percent:
Acid-bessemer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . 0.20
Other processes (Article 2.2.2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30
Copper, when specified under supplementary requirementArticle 2.2.14, min, percent . . . . . . . . . . . 0.20

2.2.4 LADLE ANALYSIS (1968)

a. A determination for carbon and copper, when copper is specified, shall be made of each heat of steel. This analysis shall be made from a test ingot taken during the pouring of the heat. The chemical composition thus determined shall be reported to the purchaser or his representative, and shall conform to the requirements specified in Article 2.2.3.

b. When ladle analysis cannot be furnished, the manufacturer shall submit a report of the chemical analysis made on three spikes selected at random from each 10-ton lot.

2.2.5 TENSILE PROPERTIES (1968)

The manufacturer may, at his option, substitute tension tests for the chemical analysis specified in Article 2.2.3, in which case the finished spikes shall conform to the following requirements as to tensile properties:

Tensile strength, min, psi. . . . . . . . . . . . 70,000
Yield point, min, psi . . . . . . . . . . . . . . . . 0.5 tensile strength
Elongation in 2 in., min, percent . . . . . . 25

2.2.6 BENDING PROPERTIES (1968)

a. The body of a full-size finished spike shall stand being bent cold through 120 degrees around a pin, the diameter of which is not greater than the thickness of the spike without cracking on the outside of the bent portion.

b. The head of a full-size finished spike shall stand being bent backwards to an angle of 55 degrees with the line of the face of the spike, without cracking on the outside of the bent portion.

2.2.7 NUMBER OF TESTS (1968)

a. When the option in Article 2.2.5 is exercised, one tension test shall be made from each 10-ton lot or fraction thereof.

b. One bend test of each kind specified in Article 2.2.6a and Article 2.2.6b shall be made from each lot of 5 tons or fraction thereof.

2.2.8 RETESTS (1968)

Spikes represented by bend tests failing to meet the requirements prescribed in Article 2.2.6a and Article 2.2.6b may be annealed and resubmitted. If the spikes fail to meet the third test, they shall be rejected.

2.2.9 PERMISSIBLE VARIATIONS IN DIMENSIONS (1968)

The finished spikes shall conform to the dimensions specified by the purchaser, subject to the permissible variations specified in Table 2-1.

2.2.10 FINISH (1968)

All finished spiked shall be straight, with well formed heads, sharp points and be free from injurious defects and shall be finished in a workmanlike manner.

2.2.11 MARKING (1968)

A letter or brand indicating the manufacturer and also the letters “HC”, indicating high carbon, shall be pressed on the head of each spike while it is being formed. When copper is specified, the letters “CU” shall be added.

5-2-6 AREMA Manual for Railway Engineering

Summary:

I am impressed at the durability of the railroad track spike as really-good-steel-for-making-knives-Myth. It just won't die, despite the discussions amongst smiths for years.

The railroad industry may call them "High Carbon", even stamp HC on the head, but they are not even close to eutectic carbon steels. It's the way they refer to them to differentiate the HC spikes (1030 steel) from Low Carbon spikes (1020 steel and not marked at all). There are some new discussions that the rail industry may be abandoning calling track spikes "high carbon" because of this confusing label. There are some discussions that the track spike manufacturers have improved the chemistry, even including vanadium and limiting other impurities. I haven't completed my study of those reported changes.

The best multiple sample, knife-shaped cross sections, performance I could generate for hardness in my shop using brine or plain water quenching is Rc45. This matches expected performance according to the Heat Treater's Guide and other manuals for heat treatment.

The conditions for an altered track spike to obtain more than Rc45 are as follows. There may be more I am not aware of yet.

Carburize the track spike under known conditions to improve the carbon content.

Weld into the spike a high carbon (eutectic or greater) steel bit. If the forge welding is quick and carbon diffusion held to a minimum, it may be possible for the non-spike carbon steel to achieve a greater hardness. This is a well known historical method of blacksmiths.

Forge a track spike from a high carbon (eutectic) steel.

These methods require other than normal shop practices to alter the track spike to non-standard. I would hope the smith reported their shop practices when making such tools to clarify that these spike knives are not standard spikes to bolster their claims of improved Rockwell hardness.

Use a quenching medium like Rob Gunter's Superquench. The limits to this are that not much more than a very thin skin of material may harden. This improves the hardness of the surface only and could be abraded away easily with use. Such quenchants do not improve the whole bar of steel. I have had simple hatchet/axes/tomahawks (made of mild, or about 1020-1030 steel) work only until the first sharpening and the edge degraded rapidly after that. Again, this is a shop practice and I would hope would appear in the sales pitch somewhere to clarify expected performance and potential performance degradation in the future.

Contrary-wise, track spikes are good for forging practice and can turn into a lot of other interesting objects that look good with big nails in them.

I don't like to be the guy who rains on people's dreams, but I do believe that the truth is more important than myths or magics.

That's a lot if good information, thanks Mike. I'll have to share that with my friend that has the forge. So far the only thing I've seen them used for is custom orders where the customer requested railroad spikes be used, and practice on Saturdays when he opens the shop to us newbys.

They are good for practice because they're essentially free, and easy to forge so ideal for new people. And Because of the low carbon content they are also hard to overheat. Higher carbon means more care is needed to prevent overheating and burning to a crisp.

Being a railroader, I get the same question at least once a month...will you make me a railroad spike knife. They first expect it for free because of my access to tons of them and then frown when I say they are useless unless you insert a high carbon chunk of billet into it for the cutting edge. NOTHING you find on the tracks can be used for knives except for an occasional spring & they are a total PITA to work with.

Don't be cheap with your time, buy some good "known" knife steel like mentioned above for learning the craft...then experiment as your knowledge grows. Once you think you have the hang of it, try to make a razor...then you have done something!

I was seriously thinking about trying to make a straight with that second billet. But honestly I think the pattern would be a waste on something so small. Who knows, maybe the next time I take something to the forge or find some scrap lying about I'll try my hand at making a razor. But first I need to process the 2 I have in the works now. I think the failed feather patern might make a good bowie.