I have noticed the same thing Landon and came to the same conclusion after talking to people. So I now make sure to preheat the dies, it helps.

Brion

Thanks Brion, I have noticed this before on other patterns but I am working 2 Ws billets and relized the second one was folding better than the first one. The cooling factor was the only thing I could come up with. Landon

Sometimes you will notice the opposite affect when drawing under a hammer that hit to lightly for the size of the work ... the out side of the billet will move faster than the core.

MP

Thanks Matthew, I had not thought of it working like that. Now i will have to play with that to see what I come up with. Landon

X 2 what Matthew said.

john

Yes, Matthew has it right. But you can also overcome this some by using shorter working sessions, going back to the forge sooner. Bump it one time and go back in the fire. Working in a narrow heat range. It all goes back to the principle of evenness. Even heating, even forging. No shadows and use bright heat. The intensity of hammer or die blow has to be appropriate to the heat and intended flow of the material.

Often overlooked but equally important is even heat extraction, whether while forging or in the quench. Uneven heat extraction happens when you forge a piece more on one side than the other since contact with the anvil or bottom die is more than the top. Sucks the heat out and makes it stiffer causing the top (hotter part)to move more. While this is inevitable, it means we have to be more conscious of our control of the timing. In a mono steel we only worry about even forging and how it relates to stress but in Damascus we can really see the visible manifestation of uneven working.

This is where some old fashioned blacksmith training plays a very important part. A blacksmith looks at moving metal in a more practical way, if you will. If a piece needs one blow due to it being thin and the heat going away fast, the blacksmith uses one blow that is appropriate in impact, using a bigger hammer in some cases, not 10 light blows. In the context of working hot steel whose heat is constantly draining as you get it out of the fire, you have to hit it hard when it requires being hit hard. There is no way out of it. 10 light blows are not equal to one hard blow when translated to metal movement.

An example of this is the very first thing you are taught when taking the blade forging class. Forging the tip on a bar. If you get it hot enough (evenly, no shadows) and hit it hard enough the innards of the bar will flow along with the outside preventing a birds mouth. Use hard, controlled blows and don't keep pecking on it after it gets out of it's proper heat range for moving metal. It has to flow. That means it has to be hot even on the inside.

When it comes to understanding the movement of metal Bladesmithing only scratches the surface. I highly recommend every bladesmith to take a general blacksmith course.