If you’re a forging hobbyist, then you’re always on the lookout for materials that you can work out. High carbon steel is ideal for any kind of blades or tools around the workshop.
In this article, I’m going to list a few areas for where to visit, and then what to look for.
Before getting into specifics too much, there are a few general guidelines on how to know if something is high/low carbon steel, or just mild steel.
For one, it’s very rare for high carbon steel to be plated. If it’s galvanized, coated, plated, or anything along those lines, it’s almost guaranteed that it’s low carbon steel.
Second, look at what the steel is currently being used for. Is it already a cutting/shearing blade? A bearing? A high-strength shaft? Or a cheap welded up bracket?
When in doubt, use Google to search something like “what is _____ made of” and you can usually get a pretty decent idea of what you’re looking at.
Third, you can do a file test to see if the steel is already hardened. This is no guarantee, since low carbon steels can be case hardened, but it can help you rule out some definite no’s.
If you’re wanting a really reliable tool for checking current hardness of steel, then you can get a hardness tester file set on Amazon for a really reasonable price. This things are extremely handy, easy to use, and I use mine all the time for getting a good idea of how hard something is.
Anyway, those are some good rules of thumb, let’s start exploring.
If your local junkyard will let you in, then this is an absolute gold mine. Technically, a high-carbon steel mine, but you get the idea.
Right away I like to look out for old cars. There are a few items that are almost guaranteed to be high carbon steel that are very useful.
Coil springs are pretty well always made up of something like a 5160 steel. Not the highest of the high carbon steels, but they’re good for large chopper knives and forging tools like punches, mandrels, chisels, fullers, etc.
Careful with removing coil springs from cars, if you don’t have a spring compressor or something comparable you could end up killing yourself when it lets loose.
Uncoiling the springs isn’t for the faint of heart, either. If you need a long, straight section, you’re probably better off choosing a better starting material. Coil springs are easier to use if you only need to straighten out a few inches.
Leaf springs from trucks are phenomenal. They’re already in a great shape – slightly curved flat bar. Just keep an eye on cracking, it’s not uncommon for a leaf or two to be cracked on a tired truck.
Those are the popular and well-known car parts. There are a few other gems that are totally worth taking, though.
Sway bars are one of these parts. They’re made of a spring steel and they generally are in an easy shape to work with.
Steering shafts, especially on older vehicles, are more likely to be high carbon, but you might get some medium carbon in the mix.
Axles are generally made from medium carbon steel, not high carbon steel.
Transmission parts like gears and flywheels are often chrome-moly alloys and case hardened, so you probably won’t get great results from them.
If you’re anywhere around lumber harvesting, there is a ton of good steel that they throw away daily from the intense wear and tear that they put on their tools.
Chains are definitely worth looking closely at. Depending on quality, some of the chains they use to beat the bark off trees are high carbon steel. Use your hardness tester file set I recommended before to know what you’re looking at.
Chainsaw blades can be used to make a really interesting damascus, but otherwise it’s really hard to make anything useful out of them because of their awkward shape. They’re definitely not good for beginners.
Old, worn-out bearings are common and absolutely ideal. Bearing steel is insanely strong and holds a phenomenal edge if you’re making a blade.
You’re going to find more medium-carbon steels than anything else at a rail yard, but it’s still good steel and often extremely plentiful.
If you’re looking for a chunk of the rail track itself, lots of guys use this to make their own mini anvils. Rail steel work hardens like nobody’s business, meaning that it gets harder as you hit it.
If you want a really thorough guide to rail track steel, then read through this article I wrote entirely about that.
Rail spikes are extremely popular for making knives, but they’re not actually high carbon steel. At best, they’re a medium carbon. Either way, people like them because they look cool. Again, I wrote another article about working with these in particular.
This is honestly the best place to look for high carbon steels. If something is made to cut metal, chances are that it’s made from something that’s going to hold an edge and take abuse.
Chisels are great, and sometimes you can find some massive ones that you can make something really cool from. Woodworking chisels are meant to maintain a sharp edge, cold chisels are meant to not shatter under hard impact.
Old files are often made from high carbon steel like 1095. Newer files are fairly often made of a soft steel that’s just case hardened. If you’re thinking of making something out of a chisel, read through my guide first.
Hammers are great options, and it’s usually easy to find a stack of old hammers with broken handles. Check the hardness with the file set first to make sure, but they usually get really hard. These can make great axes, choppers, and tools. A good hammer head should never get tossed.
Wrenches are not made of high carbon steel. They’re usually an alloy that’s something like a medium carbon steel. If you want to know what to do with a stack of old wrenches, then read through my guide here.
Out of all the options listed above, my favorites are leaf springs, hammers, and large bearings. I find that these are the most consistent in delivering the results I expect.
Working with Unknown Steels
Unless you bought the raw material yourself, you don’t really have any way of knowing 100% what you’re dealing with. This means that there’s a certain risk factor.
Lots of guys just give up on trying to recycle scrap steels because enough times they’ve put hours into a project only to find out they couldn’t properly heat treat it.
Forging functional, hardened pieces with unknown steel is going to test your heat treating abilities to the max. Expect to fail several times before you eventually get the hang of it.
This is one of the reasons I really like using that file set to check hardness instead of just one regular file. If I missed the mark with heat treating, I can find out if I just missed it by a bit or if I’m nowhere close. That can help me decide if it’s worth trying again or just abandoning ship.
Either way, the world is full of wonderful high-carbon steels that are just slowly rotting away. If you can take a piece of junk and turn it into something useful, that’s a win for everyone.