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I Forge Iron

Steel for toolmaking


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Okay folks, Thomas is chomping at the bit to hammer some hard metal. But first, which metals are best for making what? While the answers to this question are manifold, some alloys are better than others for certain uses, in different circumstances, for different people. Here is an example. If I get hired to design and build a tool and die for the local whatever factory, after I figure out the BEST alloy for the job, I will order that stock, the heck with what it costs, my reputation as a tool and diemaker is on the line. But, what if I just want to make a drift, for enlarging a hole, that I punched in a hammer head? Can't I just grab a piece of that wicked hard stuff I got from under that car that just exploded in the driveway? Maybe, maybe not. Heres where it gets tricky(and where the disagreement will likely originate), First of all, what am I making the hammer head out of? Why does it matter? Depends on the constituents of the alloy. As Thomas pointed out, some alloys of steel are HARD even when hot, like red hot, even orange hot. So that means that whatever metal I force through that Hot Hard metal, needs some special qualities. Like toughness, and impact resistance, and ,(actual metallurgy term) Red-hardness. Red hardness is the ability of a metal to stay hard, when red hot. Back to the drift. Should I get out a tool steel catalog, determine the qualities I need, see which alloy most closely meets them, order the steel, pay the piper, pay the shipping(ouch), or should I use this piece of a jack hammer bit that is almost the right size? Since it is red hard, tough as all get out, impact resistant, and AIR HARDENING, I'm going for it. What does air hardening mean to me, right now? .(wheres Quenchcrack when you need him. Good luck in the hospital QC) ,After I take it out of the HOT chunk of steel I am working on, it air hardens again, all by itself, with no help from me. There may be 1000 ways to skin a cat, but some of them are easier or just better than others. Yes I know that early jack hammer bits may not be air hard. More to follow.

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I've started making slot punches and chisels from H-13. amazing stuff. It's important to remember that air hard tooling is most likely as hard if not harder than your favorite hammer. You can put all kinds of dings in the hammer face you spent an hour dressing and polishing . Have a 'consumable' hammer that you don't care about to use on air hard punches and drifts. The consumable hammer should be tempered way soft or annealed to keep from chipping.

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Don't forget the difference between a prototype and a one-off and something you will be using 50 times a day every day for years!

In general coil and leaf springs are a decent tool for tooling. For specific tools that will need to hold a shape when burried in hot steel high alloyed (expensive) steel may really be the best way to go.

My hardy is the broken off end of a jackhammer bit forged down to fit through the hardy hole and forged thinner towards the edge. Made it close to 20 years ago and it's still going strong---though I prefer it softer than the hammer face as it's simpler to dress when one of my students messes it up.

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Most jackhammer bits are not red hard. And they do not spark that way. I received a broken pavement breaker bit from a blacksmith who "qualified" it as red hard. It wasn't, but I found that out after the tool I made from it failed. The steel turned out to work fine for less demanding applications, with a water quench :o. This blacksmith sharpened these bits as a large part of his business, but only bought new S-7 for his own tools. He did not recycle broken bits. They were for passing out to the newbies who occasionally visited him...

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Alloy selection is one of the really fun things that metallurgist get to do. We have the opportunity to choose from everything ever cataloged. Let somebody else try to find it and work it. My favorite is Unobtanium. Seriously, anyone can buy good alloy steel, shape it and have it professionally heat treated to get a fine tool. It is left to the smith to take a worn out, rust-pitted part that fell off of a 1962 International, forge it with style and grace, heat treat it BY HEATING IT TO NON-MAGNETIC (:-)), quenching it in dirty green water, brushing it up and waxing to a high shine, and putting it to work for about 20 years!

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Thank you for all the great replies. Glen asked me to provide references so others could verify what was said. Being who I am, I had to wing it, stream of mind so to speak. Naturally, now I can't find the particular book I am looking for. But I will provide some foot notes and let you guy correct what I get wrong. Starting at the top; MikeHr, h-13, possibly the most popular air hardening alloy, at least among blacksmiths. Thomas, what exactly do you mean? I somewhat agree, with Thomas on spring stock. It is great for making tools of many types. With a carbon content generaly between .6-.8%, It can be readily hardened to a sharp edge for wood cutting, or tough and strong(softer) for a wrench or pliers, plus it makes great springs. Please be aware that present day spings can be deformed cold however, not sure what has changed to allow that. Evfreak, how does red hard spark? You do realize it is a low carbon alloy right?(Metals Handbook) QC, thanks for not peeling me apart like an onion, which I know you could have done. 6013, see my previous post on s.s. quench tubs, the cleaner water was the main reason for the design. B.T., would like to compliment your truck, but the link didn't go. Finaly, todays point is, There are two different kinds of people in the world, those that believe there are two different kinds and those that don't. Different strokes for different folks and all that. Here is an example. I make a lot of bolts. Not the crossbow type. That means I make a lot of bolt headers. A piece of s-7, 1.5" diameter, from Mcmaster-Carr, lists for $175 plus shipping. My bolt headers are only 1.25" long. If I were to order that stock, to make one tool, in short order, my steel inventory would surpass my net worth. When I find that book, I can explain my reverse engineering method, of finding tool steel in the wild, where it can live, and be had for free. Thanks for listening.

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Arfist, it never occured to me to peal you like an onion. You said nothing to warrant it and I agreed with what you said.. Although, I was told by one of our Computer Scientists at work that there are actually 10 kinds of people: those who understand binary and those who don't. :-)

Edited by Quenchcrack
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Right Quenchcrack, freshman year engineering consisted of two computer courses, binary and basic. I chose a different path. I did not touch a keyboard for most of my life, reasoning that knowlegde is like a pie and the less slices you try to take, the bigger your one slice will be. The slice I chose was metal. Finaly, with the developments of windows and the internet, the computer became too good of a tool to ignore, so now I am here, trying to add to its usefullness, and continue my education. But I digress, let us now analyse; Mike brought up h-13, a member of the chromium hot work group. These are deep hardening steels, which will essentialy harden all the way through, in small enough sections, IF HELD at critical plus, for soficient time for the heat to travel all the way through, also known as soak time or soaking heat. Whatever tool you are hardening, including knives need sufficient soak time. Thin or heavily machined metal require great care, skill, or knowledge to properly heat treat. This is what Quenchcrack meant when he said anybody can send it out and get it heat treated. The easiest and arguably best way to heat treat metal is in an oven designed for that purpose. However, most needs of the blacksmith can be met with a forge. The only caveat with air hardening alloys is that normalizing ( heating to the upper critical limit, soaking, allowing to cool in air, also known as open air annealing) will cause complete and total hardness. Which brings us to Evfreak. Even h-13 has a limit as to how red-hard it really is. Frequent cooling with water will entend, the work time, work capacity and life span of tools made from the chromium hotwork group. It is also tough enough to be quenched in water, but that is not nessasary. Are you sure it was at it's upper critical temp, or more, and had sufficient time at soak?. Plus it may not be air hard. High carbon tools, while very hardenable, can require frequent dressing and rehardening. That is why air hardening allows were developed. Which brings up to hunt for steel, which is different from gathering steel. When gathering steel, we must be armed with methods, tests if you will, to closely guess their properties. Hunting, is different. We determine the alloy we wish to aquire, by use of a list from a book, which lists all the different alloys of tool steel, and most of the items ever made from said alloy. Then we deduce, from that list, what object, near or available to us, is made from that alloy. Such lists are available in many comprehensive metalworking books, but much more detailed and complete in certain books such as those published by the American Society fo Metals(ASM), but also, ASTM,SAE, you get the idea. The advantage to this technique, is that the information for optimum heat treating becomes a known. Next week, using gathered steel.

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Hi arftist. You asked about spark testing. Spark testing for checking the red hardness of steels absolutely requires standards. These are available over the Internet or from kind fellow blacksmiths. The main alloying ingredients which contribute to hot work capabilities are molybdenum, chromium, or tungsten. See my gallery photos for ways to distinguish the molybdenum spear point. For chromium, most commonly known in automobile spring steel, look for "flowers" along the main shaft. They look like little hairs before the burst end. For tungsten, get some HSS drills, or known M-2. It affects the color and length of the sparks. Drill bits spark with few bursts, and look like low carbon, but they are very hard and hardenable. The color of the sparks is a dull red. Of course, you could always grind TIG electrodes, but these look nothing like steel.

A smith once told me that you could judge hot work potential simply by forging the steel. He said that 5160 and S-7 are similar under the hammer as they are cooling. I am not sure about this, but he has punched a lot more hammer heads with OCS than I have with S-7, so I defer to his experience.

As for cost of tool steels, your observation of high prices from retailers is correct. I have found that Ebay sellers such as Pacific, NES, or Speedy Metals sell tool steel drops for approximately $1 per pound plus shipping. I bought a block of S-7 and D-2 about 3x2x1 for a very reasonable price. You can just cut slices off the end, since they are sold dead soft annealed.

Here is an excerpt of a post I made some time ago:

"The H-13 pieces listed on ebay at rem's (cut offs) from our production cutting o
perations. Here's a sample of sizes (in inches):
2 x 3 x 27, .75 x 3 x 36, .75 x 2.5 x 33, 1.5 x 4.5 x 13, 1 x 2 x 12... Let us k
now if these sizes will work."

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  • 3 months later...

Has any one ever made any tools like an axe from a piece of Railroad track, I need a squaring axe and I have alot of pieces of Railroad track as a matter of fact I have a pile of Railroad metal including spikes tie plates and track, I have discoverd that spikes made after 1970 something are considered by the Railroad to be high carbon and accually say "HC"on the head and they say that these are equal to 1040 steel but I cant find any info on the track, it is probably use hardend but is it suitable for an axe.

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I am citing the Arema (The American Railway Engineering and Maintenance-of-Way Association) 2007 document, Part 2 "manufacture of Rail"

Standard rail steel:
.74 to.86% Carbon,
.75 to 1.25% Manganese,
.10 to .60% Silicon
Minimum Brinell (of unhardened surface) 310 or 370 dependant of grade ordered.

Low Alloy Rail Steel
.72 to .82% Carbon,
.80 to 1.10% Manganese,
.25 to .40& Chromium,
.10 to .50% Silicon
Minimum Brinell (of unhardened surface) 310, 325, or 370 dependant of grade ordered.
My document shows the following breakdown for grades:
SS = standard strength (brinell 310)
HH = Head Hardened (brinell 370)
LA = Low Alloy Standard Strength (brinell 310)
IH = Low Alloy Intermediate (brinell 325)
LH = Low Alloy Head Hardened (brinell 370)

I understand a lot of very good khukuri are made from rail in Nepal. Not sure what the Nepalese surplus rail is like though!
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