"Fishmouthing"?

[Shamus Blargostadt]

Trying to forge a knife tip without cutting it first but I'm getting the wrong shape. Everything I try to do seems to make it worse. Is there a technique to forging this out correctly?

 

 

[Buzzkill]

Basically what I do is set the bar stock on edge on the anvil with the end that needs to be shaped away from me and then hammer the top corner back  towards myself.  I'm not a big fan of tongs when I make knives, so I usually weld a section of rebar or round stock to hold on to.  This technique does take a little while to do since a lot of the force ends up going into your "tong hand" instead of down into the anvil, but it does get rid of the fishmouth effect with practice.  You can use the horn on the anvil for some of this too as the curved shape allows you to hit into the steel with something solid behind it a little bit.  As a side note if you start with round stock (like drill rod) that has been hot  cut this isn't much of an issue since the shape naturally formed by the hot cut mostly keeps the fishmouth effect from ever occurring.

[Frosty]

Forge the tip first. Drive it in at about a 45* angle till it's close to the finish width then work back by driving the angle down into the center.

What's happening when it "fish mouths" is a result of basic physics. Force ALWAYS takes the path of least resistance. This means the hammer's energy as imparted into the steel finds an easier path on the surface so the steel flows sideways where there is less resistance from surrounding steel.

You can see this with modeling clay if you press with your thumb near the edge, it will mushroom more than bulge in the center. There is less resistance at the edge so that's the way it goes.

Forging directly into the corner provides equal resistance to movement all round so it goes (sort of) straight in. It will bulge getting thicker take care of this quick, don't let it build up or it'll drive the section you just forged in back out as path of least resistance.

I've known a couple bladesmiths who ground a 45* on blanks before they started forging because, "it's impossible to forge the 45*," I figured that was a statement as to their skill level.

I'm not a bladesmith guy, I just like playing with fire and beating really hot steel with hammers and that's what works for me.

Frosty The Lucky.

[Shamus Blargostadt]

Thanks guys!

[rockstar.esq]

I've heard that "clip point" knife pattern came from clipping the corner off a piece of stock prior to forging.  I have absolutely no idea if that's true or not but it's got appealing logic.
 

[JNewman]

Three things cause fishmouthing working too cold, blows too light or working too close to the edge with straight down blows.  The first 2 things cause you to move the outside of the  Nothing is worse when rough shaping a piece than light taps with not enough heat.  As others have said work the corners in first, but make sure you do that with solid blows and with a good heat.  A couple of good blows then flatten maybe a couple more corner blows then back in the fire.  

When you are cutting your stock you can cut enough for 2 blades then either cut the stock in half on an angle or hot cut it.  That way you are pre forming your steel but not wasting any. 

When you forge the end of the bar in like that you are actually upsetting as you thicken the bar while making it narrower.  That bar looks like it exceeds the 3:1 rule for upsetting which can make it difficult to forge in the  taper that way on a flat bar.