Getting creases when forging

A

artney_iv

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Apr 19, 2013
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I'm new to forging. All I've really done is a couple hooks and I've toyed with beating a couple railroad spikes around. The goal is to make a tomahawk out of one and I've got solid ideas on how to do it, most of which I've executed to some degree of success but my biggest problem on many of my experimental attempts has been getting the head of the spike to hammer our flat to create the blade. I often get a really ugly fold or crease created along one side and down around the lower arch of the blade. Additionally, the cutting edge itself usually contains a crease or two that run down it (if that makes sense). I know it's from just not hammering evenly and altogether being a newbie. That realization being firmly in place, I'm running to the pool of wisdom for some advice. I've never had any kind I formal teaching on smithing or forging so is there anything anybody here has learned or discovered by trial that's helped them? It's often hard to see those creases as they're forming when the metal is glowing. When it cools off and turns dark again, they stick out something awful though.

As always, thanks in advance for your time and help.
 
Creasing or folding is usually a result of the steel not being hot enough when being struck.
 
Yup, a not-hot-enough piece of steel will deform on the surface and not change shape like a nice yellow hot piece.

Until you can get some hands on instruction, the best advice I can give you is to watch really carefully as you forge, inspect your work piece before you put it back in the heat, looking for creases- blacksmiths call them "cold shuts" to distinguish them from intentional welds.
Stop and grind it out before you go any farther.

There are a lot of great blacksmiths in Mo., and just about everyone who mashes steel just loves to share what they've learned- find an experienced smith and bend his ear, you'll have a lot of fun and he'll point out some stuff that you'd never have noticed on your own.
 
I've seen a couple of these on a few blades I've forged before, though I don't forge most of mine - choosing to do stock removal when I can. I don't know for sure if the creases might "return" when normalizing on something like a tomahawk or axe head, but in case they do, don't make my same mistake - normalize BEFORE doing a preliminary polish. I've had to go back and re-sand blade blanks because as they normalized the alleviated stress resulted in what I've heard called "steel memory". Just my two cents of what to expect and what not to do.
 
That's about as easy a fix as one could hope for. I was thinking that it was primarily due to the flare on the end of the spike where the head surface comes out not being hammered down correctly. I'm sure that has a hand in it but I can see where more heat would allow for a little more wiggle room in having to come down with my blows at a perfect angle. Thanks. Thanks for your advice on normalizing too, Ninja blacksmith. I'm not to that point yet but that'll doubtless save me some trouble when I get there.
 
You said that it is most pronounced where you are trying to change the shape of the spike's head, so I believe that your problem might be from a few other things than what has been posted (so actually your thinking might be correct). One, is temperature. It might not need to be necessarily hotter, but the item given time to equalize in temp all the way through. If you are hotter on the surface than in the core, the outside moves much faster than the inside because it is more malleable. Two, is the radical difference in cross section between the head and the spike body. As you hammer the narrow "flange" of the head down to flatten it out, it will want to flare out or fold over ~ especially if your hammer control isn't great. You need to alternate your hammer blows from driving down the flange with ones that will correct the flare and folds. Hope that this made sense.
 
If I understand right, this could also be amplified by light blows. This, added to not enough heat, not enough soak (uneven heat throughout) could cause this. When reducing stock a lot, this will happen, unless you try hard to stop it. One way to fix it is with a grinder, just grind out the "fish lips" as there are called sometimes. You can help stop this by forging the corners back at a 45 degree angle first, before forging on the flats. A common spot for this is when forging the point in a blade.

Hope this helps.
 
That helps a lot. I never even considered just grinding the fish lips off before forging, but yes, that's exactly where the majority of the problem is. Thanks to both of you.
 
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