Frustrated with forging bevels

[Fox]

I shape the knife do the tang and it looks right about how I want it, then I hammer in the bevels and the knife bananas like crazy and messes up the shape of my tip and is a real pain to keep straight … how do I deal with this??

[mmattockx]

I don't forge (yet), so take this with however much salt as you like.

When you hammer bevels in the blade has to curve more to accommodate the material moving. You need to lead that with your initial shape so that it curves into the shape you want when fully formed. That means making it straight or even curved the wrong way when constant thickness, with the knowledge of how it is going to move as you form the bevels in.

Wayne Goddard's $50 Knife Shop and The Wonder of Knifemaking talk about this and show examples of pre formed blades and how they change as the bevel is worked in.


Mark

[Don W]

You know it's going to banana, so reverse banana it as you forge. That is what I do.

[TRiggs]

To counter your blade turning into a banana you must forge it straight to start with, don't just forge in the bevels do it all at once a little bevel work and inch or so both sides then work the spine and your distal taper to the tip do that until you have beveled the whole blade and remember your forged in bevels only account for a third of the blades width.

[Mr. Woolery]

There are two things to do to deal with the buffalo skinner shape.  First, as noted above, is to preform the blade.  You have a flat bar with a tang on it. You know what side your bevel will be on.  You know the bevel is going to result in a banana curve.  Heat that sucker up and gently forge it to a reverse curve. The ideal is that your bevels will exactly compensate for that reverse curve.  (Seriously, just put it over the horn of the anvil, as if you were going to cut the anvil, so edge-wise, and tap the back to form a deep forward curve.  It takes one heat and then you forge the bevels at the inside of the curve.)

There are times when that preform doesn't do the whole job, though.  What now?

Heat your blade up to forging heat.  Set the spine on the face of the anvil. Like you are going to have the knife edge cut something dropped on it.  Gently tap the very edge.  Like you are trying to split your hammer by dropping it onto the knife edge.  It doesn't take much force to bend the steel in any direction, even if it takes a lot to really reshape it.  You are just imparting a bend to the steel in the direction you need. 

The result will be a straight spine and a slightly wavy edge.  Easily tapped into line again.

If this was unclear, I can try to take some pictures this evening.

-Patrick