Heat Treating Nails...a Beginner's (possibly dumb) Question

[BowtoEd]

Hello all,

 

I've been reading about blacksmithing, knife making, metal working, etc, for several years. Tonight I actually tried something and found that all I know conflicted with reality.

 

I bought a pound of steel nails at Home Depot. The reason was to use them as rivets in certain projects. I have a pop-riveter but I think those rivets would be terrible in comparison to peened steel rivets. I build vacuum tube amps and I like the chassis to be rock-solid. I subscribe to the term "battleship construction" for my transmitting equipment because they're built with lots of metal and lots of fasteners.

 

Anywho, I annealed a few nails tonight so the peening process would go easier. I heated them to red-orange on the gas stove and then, once they stopped glowing, set them on a board atop the counter so they could cool slowly. I heated the head-end of a dozen, then heated the head and point end of another one. I took at it with a hammer (unfortunately, I don't have a ball-peen so I used my larger claw hammer) and tapped it against my anvil. I have an actual anvil but it's one of those 1 or 2-pound jeweler's anvils. After about an hour of hammering and filing, I went back to harden it. I was trying to make a small knife out of the nail, just to experiment with this stuff.

 

My process for hardening comes right from everything I've read...heat it to red-orange just as done with annealing. Once there, instead of letting it air-cool, quench it in water or oil to remove the heat quickly. Well, not wanting to waste oil I tried water first. After five minutes, I took it out and pressed on the side. Without much pressure, the blade bent over easily. I straightened it out and tried again with similar results. The blade was softer now than it had been while I was working it. I poured a little olive oil in a cup and tried with that. The blade was softer still.

 

Clearly there's something wrong with my process. Maybe nail steel is a strange animal that just won't behave. I'm not going to buy special tool steel or build a forge capable of heating a large block because this was just an experiment. I do want to figure out why my process didn't work though.

 

Thanks for the information. I've read some of the posts here and it seems like this is a really solid knowledge base.

[bigfootnampa]

The steel in nails has very low carbon content!  It will not harden!  Cut nails or concrete nails have a LITTLE carbon and will harden slightly.  

[Chinobi]

"steel nails" covers a lot of ground :) without knowing where you are i will default to my own experience looking at home depot and lowes for high carbon nails as premade small hand tool blanks.  HD didnt carry beans in terms of appreciably harden-able nail stock, and lowes gave me the run-around claiming that they were 'getting another truck in on thursday' (without saying what was IN it).  i eventually ordered some cut masonry nails from tremont nails, which clock in at a mere 35 points of carbon, which is not fantastic for much other than making it that much more irritating to file/grind/shape without heating them up and forging to profile.  your experimental quenching results are consistent though, water is a faster quench than oil so it will be somewhat harder with the water than with the oil, somewhat.  you could try knocking together a batch of superquench to try to squeak out a tiny bit more hardness, but i probably wouldnt waste the time.

 

if you still have the box or label and can tell us exactly what you bought you might have a chance at some answers, otherwise, theres not enough info provided for the experts to give you anything more specific =/

[Dogsoldat]

would the nails not be at maximum hardness out of the box from work hardening?  Super Quench might buy you a little more,  but common nails are poor stock to start with,  so many bits of scrap out there that will perform so much better

[BowtoEd]

Okay, so nails were a poor choice for a blacksmithing experiment. The problem is that I would need something pretty small if I want to rerun the experiment with new steel. My stove burner seemed to work for softening the steel but not hardening it. I did soften several spoons today. This was for making coat hooks. That turned out well except they didn't polish out as well as I'd have liked. The nails make good rivets although I think I want a harder hammer to peen them. What should I expect to pay for a great ball pein hammer?

Ed

[Neil Blythin]

Garage / yard sales are a great place to find tools (especially this time of year). You should be able to lay your hands on an old ball peen for a couple of dollars.

Sounds like you're in desperate need of a better heat source. Even if you plan on sticking with very small scale work, you may want to consider making one of those small (one or two brick) gas forges that are run off a standard plumbing torch. I've never made one, but have seen a lot of videos where they look pretty simple yet effective.

As for stock, drill rod comes in some very small diameters...

[swedefiddle]

Good Morning, Ed

 

If you can get something red hot to forge, it also is hot enough to harden.

The ability to harden something depends on it's chemical composition. Low carbon will not harden without a dream.

Medium carbon is good for working tools as it won't fracture as easily as poorly heat treated high carbon.

 

I think there is history in this web-site about heat treating knives. Read it slowly and allow the knowledge to absorb. They have covered heat treating in great detail. There is NO ONE WAY, All steels have their own process and quenching mediums. To be correct, all metals have, Ferrous and Non-Ferrous. 

 

By the way, nails do make good rivets, because they don't harden. Working metal too cool will work harden the piecs and they will crack/break. That is different from trying to heat treat something. Copper NEEDS to be annealled after bending because of work hardening.

 

Neil

[ThomasPowers]

I have to assume you are in the USA from the stores mentioned; but if you want more specific answers a general location helps a lot.   Here in the USA, (Ohio and New Mexico), I have so far bought 3 buckets of ball peen hammers never having spent more than a dollar a piece.  Note I do spend a considerable amount of time at fleamarkets and junk stores and the odd garage sale hunting stuff down; but I don't watch TV (don't have one!) and so it's part of my entertainment budget...  Now most of the cheap hammers will need new handles and so I pick up a bunch of them when I find them cheap as well so that would bring the price for a hammer up to US$2...

 

Note heating to the critical temp and cooling in air is NOT ANNEALING; it's normalizing.  Cooling much slower than that is annealing and will make it softer.  (I once showed an old trick to some folks trying to use Tremont nails for a viking boat build. They were having trouble getting them soft enough to use a rivets and I showed them the trick about massing them together and/or using a larger helper piece to provide enough heat to slow down the cooling.  I liked to put them in a SS coffee creamer, heat to temp and then shut down the propane forge with them still in it.)

 

If your reading has not discussed the difference between Annealing and Normalizing (though armourmakers often use the wrong terms!) and the need for a certain level of carbon in a steel to make it harden---heating to red and quenching in water will soften steel if it is extremely low in carbon!---I would suggest reading better sources:  "The Complete Bladesmith"  James Hrisoulas for example.  If your local public library doesn't have a copy ask them about Inter Library Loan.

 

Also look up "One Firebrick Forge" on the net, a simple plumbers propane torch will run a one fire brick forge up to forging temps and, as mentioned before, Drill rod is good knifemaking stock and available at good hardware stores.

[caintuckrifle]

(After you get some better steel) When you are hardening get yourself a magnet- as you heat the steel touch a magnet to it. As long as that magnet will still stick you're not hot enough to harden when it won't stick quench it immediately until it is cool to the touch. When the workpiece comes out try to file it- if you can it is not hard and you can try again. Then there's tempering- but that's a whole different story...

 

This is just a general rule that works with most carbon steels that I use. 

[BowtoEd]

So, I'm not sure where to look for some better steel. My target is something that can be bought cheaply at thrift stores or Wal-Mart for high-volume, low cost (hence, the box of nails). I don't know how to discover the makeup of steel in things that I find around.

 

What about hack saw blades?

[the iron dwarf]

a coil spring from a car suspension

a cold chisel

avoid anything that is plated, the fumes are not good for you

 

if you get into forge welding then bicycle or motor cycle chain

 

hacksaw blades can be worked and hardened again but are a bit thin

[Chinobi]

Look up 'spark testing' as a general guide to composition, it's not conclusive but it's a start. You can also test harden and break one and check the results. What exactly is your project? Plentiful cheap rivet stock, or large quantities of really tiny knives...? Many members here have produced very fine blades from old files, which are typically high carbon and can often be found on the cheap at garage sales and swap meets etc.

You can also call the manufacturer and ask them what the composition is, they may not divulge, but you have nothing to lose by asking.

Presuming you are in the US (phone doesn't show profile loc so sorry if you already updated that) you can get a 12 oz ball pein from harbor freight for 3$. Is it 'great', far from it, will it get the job done, definitely.

[Chinobi]

My bad, just checked the ones I have, they are 16oz

[ThomasPowers]

Stop by my place Saturday and if I'm not working in Mexico I'll give you a couple of pounds of "knife grade" steels.

 

Don't know about buying stuff at big box stores they are always so much more expensive than fleamarkets, junk stores, garage sales, scrapyards and road kill steel...

 

Seems like most mechanics have a pile of coil springs around the place somewhere too.  1 of them cut down opposing sides makes a dozen or so ( pieces each one suitable for a good sized knife and having a lot of the same stuff you can actually figure out the proper working and heat treat of it!  (actually for a beginner 3 cuts would be better as you want to start with smaller blades to shorten the learning curve)

[caintuckrifle]

Check out: http://i35.photobucket.com/albums/d200/ptsideshow/Tools/WElding%20equipment/junkyard.jpg 

 

For thrift store quality steel look for tire irons otherwise known as lug wrenches, they are plentiful, cheap, and generally good carbon steel.

[ThomasPowers]

Of course such listings are notoriously iffy---like bearing races being 52100, the small ones are; the large ones are more likely case hardened 9620.   Also the jackhammer bits being S5  We had a fellow who has sharpened over a  million of them and only a handful were anything fancier than a medium carbon steel. (Machinerys Handbook says that S5 would be good for jackhammer bits and it certainly would---of course Titanium would make excellent car bodies and solid gold makes a truly superior frying pan ---you see any around?)

[BowtoEd]

First, I do live in the US for all those asking. I'm in the Pacific Northwest a few hours from the Canadian border.

 

I looked and I couldn't find a picture of the nails I bought. I'm not worried about it; I've given up on the idea of cold-forging nails and then hardening them. For now, I've cut some strips off of an old carpenter's saw and I'm going to try playing with them.

 

My objective isn't to make anything in particular. For now, I'm just trying to experience the basic process of heating steel to soften it, hitting it with a hammer, then heating it again to harden it. Maybe I will get into making small knives or mechanical parts for radios (for example, rotary mechanisms for engaging the tuning parts). The sky really isn't the limit but I like learning about new things.

 

For now, I won't be investing much money in this. Maybe I'll get a ball peen hammer to replace the claw hammer I've been using and maybe I'll splurge and get a bar of tool steel from Jantz. My mentality has been, "if I walk into a store, what contains metal that will be useful for forging?" I don't intend on building a forge as of yet and I will continue to use the small flame on the kitchen stove. Eventually I might build a forge but I want to see the process working first-hand. Maybe the judgment I'm using is flawed.

 

I'm also not interested much in hot-forging. Because I don't have a designated area just for blacksmithing, I think it's better to limit my involvement while I learn what is going on. That's all I really know for now; once I figure out a bit more I think I might get involved and maybe even make a few knives.

 

Ed

[Chinobi]

Look up the North West Blacksmith Association (NWBA) and see if there is anyone within range that you can link up with, im certain you can find someone who will welcome you into their shop to experience the process with the right tools in a safe environment.  I think you will find that experience infinitely more enjoyable than what you have described so far.

 

if you want to play around with cold forging you could go for copper (though i cant think of anything offhand that would be somewhat off the shelf and contain a good sized piece that can be salvaged).  copper can be annealed on the kitchen stove and then worked entirely cold until it work hardens, then anneal again/rinse/repeat.  

 

check out this thread as well where we were exploring the possibility of forging tin/pewter cold and the recycle-ability potential of it, never came to a conclusion though =/

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also, if you are intent on continuing to work using your gas range as a heat source i wouldnt even bother picking up tool steel, i dont think you will be able to get it up to the correct working temperature, and if you could you would need to set your anvil(or anvil substitute) up in the middle of the kitchen and actually hammer it right there, which unless you live alone, is not going to go over well with the other people in the house! (not to mention is hugely dangerous)  Tool steel is harder to forge than mild steel even at the correct forging temperature, working it too cold would be quite a chore especially with a light hammer, plus working tool steel too cold puts a lot of stress into the metal, so it will be highly likely to crack and break, which is really depressing when it happens a few hours into the project!

 

long post short: find someone with a proper shop and ask to spend an afternoon under their guidance, or find a class at a shop or school affiliated with NWBA and get your feet properly wet :)

 

Good luck!