Tips for final straightening during forging?

J

JoshEarl

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Sep 30, 2007
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I'm continuing to work on forging my blades to shape, and one thing I'm curious about is how you ensure that a tapered blade comes out perfectly straight. I love forge-finished blades and would like to minimize the amount of grinding that I have to do when the hammer gets put away.

I've thought about making a tool that would consist of two flat pieces of steel with a loose pin at one end. You could put the tapered blade in between the two pieces and give it a few good taps. The top piece of the tool would conform to the angle of the taper, and it might help even things out.

Any tips for getting an arrow-straight taper that doesn't need to be corrected on the grinder?

Thanks,
Josh
 
As this may not be the answer your looking for and I'm not trying to be a smart ass, but PRACTICE is my response. I find the more I forge the better I get. It sounds like you've got the basics and there's not much more than that when it comes to forging blades. My final taps are with the blade bevels flat with the anvil with the ricasso area hanging over the edge and tapping lightly flipping, checking and tapping till I'm satisfied it's straight.
 
Take your time with it. Look at it from both ends not just one. It will get easier with practice like Mike said.
 
...try it and tell us how it works for you.

anything that I have tried to bend to get straight, I have had to 'overbend' past straight, so it comes back to straight.

It takes a lot of eyeballing and a wooden whacker helps.

and

good normalizing before HT
 
Somethings that J. Neilson showed me that really help me:

After pulling the blade out of the forge, the edge will cool faster than the rest of the blade. If you view the edge straight on, as it is cooling, it will darken as it cools against the background of the still glowing blade. This makes the edge more clearly visible due to the contrast with the rest of the blade.

Another is that a twisted blade is better remedied with a vise and tongs rather than a hammer.

An old baseball bat makes a good wooden whacker. -Doug
 
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A wooden Swacker ( Zwacker if you are European) is a good tool to have.Anything from a cut off baseball bat to a lignum vitae mallet works. You can work red hot blades with it and leave no marks.
The other trick ( well, its not a trick, its a skill) is to use a lighter hammer toward the end of the forging. I move from a 1.5Kg to a 1Kg and often finish with a .5Kg hammer. As said, use a vise for twists, the more you hammer them ,the worse they get.

Unless you are going to put it under a 20 ton press, your tapered die idea won't work for straightening blades. If you do the math, you will see that a hammer blow will be so greatly reduced by the area covered as to be totally ineffective.

Stress relieve all blades after the forging is done, and again after grinding.
 
Mike Quesenberry said:
As this may not be the answer your looking for and I'm not trying to be a smart ass, but PRACTICE is my response. I find the more I forge the better I get. It sounds like you've got the basics and there's not much more than that when it comes to forging blades. My final taps are with the blade bevels flat with the anvil with the ricasso area hanging over the edge and tapping lightly flipping, checking and tapping till I'm satisfied it's straight.
Click to expand...
This is about it, it took me a while to get it, but if somebody shows you it will save a lot of time learning on your own.
When hammering I hammer in one spot and move the blade around under the hammer, if you make a divot stop and re heat. If you dent do not wait until the last to fix it or your blade will end up to be to thin.
When I am done I as above tap it to smooth things out, I let it cool a little more then normal and keep taping to get the little wrinkles out.
Cheers Ron.
 
One thing I try to teach my students is hit it once then look at it. If you have a spot that needs to be moved over locate it and tap it once. If you hit it too hard or too many times you will move it too far the wrong way. This is why I hit it once and reassess. This is done in the final straightening and at a slightly cooler temp. But like all the others have pointed out practice will make it easier.
 
What also helps is to get some chalk or soapstone, and run it along the spine and edge of the blade to make it show white before you sight down the length, this makes the edge stick out more visibly and makes it easier to spot waves and curves.
 
Practice.

And correcting all "problems" while they are still small and manageable. Dedicating the last portion of each heat--or, alternately, the entirety of every other heat--to a quick straightening will save you lots of time and agony down the line.
 
good tips from everyone, this is something I was having trouble with myself. I decided to use stock removal for my last few just to get better at grinding but I will be going back to forging very soon and hope to improve my skills.

I was having a lot of trouble getting my bevels even on both sides, to straighten I just used a small hammer at the end with decent but not spectacular results, I plan on trying a wooden hammer/bat/club in the future.

My plan to start out is to forge the bevels to 50-75% of where I want them, then grind them the rest of the way and see how it comes out, maybe work my way up to getting them 80-90% of the way there after doing a few. I'm also a big fan of the forge finish, the finish that Forge Tempering leaves just isn't the same (I tried that lol).
 
one thing I have found that helped me immensely is to do the blade in stages.

I used to try to get the bevels all nice and neat before working the choil or tang at all. invariably I would mess up the blade trying to do the handle.

what I do now is
-establish the tip
-taper the bar
-get the bevels roughly shaped (at this point my edge is still nearly 1/8)
-straighten
-work in the choil
-straighten
-refine the plunge
-straighten
-refine the tang/handle
-thin the edge down to finished dimension
-straighten

when I say straighten I will take as many heats as necessary and keep going until it is straight.

one of the biggest things to learn is NOT to overlook issues until later, they just get worse.
 
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