There are lots of tools to use in the forge. Don't fall into the trap of thinking we have to do everything with a hammer. That's foolish.

(One thing I have done is make a set of dies that are 3 inches by 10 inches. After the blade is forged, I bring the blade up to about 1500 degrees and give it a squeeze to get it straight. Easy peasy)

Do you have a vise in the forge area?

After forging the blade I might put it - edge up - into a vise and look down it from one end to the other. Put it in the vise with the ricasso and spine lengthwise in the jaws with the edge accessible. Take a crescent wrench that is adjusted to just slide onto the cutting edge and while glowing hot, tweak the edge until it is centered.

Blacksmiths of old used every tool they could possibly get their hands on to perform their function of forging objects. All these tools kept them in a very competitive business. They needed to get things DONE.

You have the same responsibility, so don't think you have to do everything with a hammer. That's Hollywood.

I also have some straightening dies for my press. If you don't have a press, take two pieces of angle iron (2x2x3/16 works well) and lay them over the jaws of your post vice and use the vice to straighten the blade. Putting the spine deep into the jaws and leaving the edge just poking up over the top will let you really see where the center is/should be. Then you can tap the edge lightly to straighten and center it.

I am going to disagree with both these gentlemen..  for basics steps like straightening, forging in bevels reliance on jigs and fixtures is limiting and a crutch in my opinion. To each there own, and I am not going to criticize any one for doign what they need to to make a living. It is just for me I have found technique is the most reliable and adaptable jig. 

to the at end I can think of several things to help you. First is a trick I learned from Mace Vitale JS color the edge with soap stone (welders chalk) this makes it easier to see against the forged background.  and feel free to reapply the soap stone as needed. When sighting find a straight line in your shop (a door frame, flooring joint. a poster on the wall) and use that to sight along. Check the knife from multiple directions sight from the tang from the point look straight down on the edge. once i think i t have it straight I like to stand the knife up on my anvil and take a step back I'll often see things then that I missed. (its also a bit of a flex that I forged straight and even enough to stand it up on the spine)  if it is to thin or the shape will not allow for that (like a chef knife or a kukuri) I'll use tongs to support it on the anvil or put it in the vice. 

As far as straightening, there is an order of operations to this , and it is isn't followed you will struggle. First task is to center the edge on the ricosso. To do so the easiest way is to "not screw up" that isn't likely so ignoring that option for now, the next easiest way is to sight it and look as which side is heavy , place that side down with the plunge in line with the edge of the anvil. (with a nice orange heat) then give one firm blow to the  ricosso to push the bevel to center. sight again. as long as the ricosso is off the anvil it will not get thinner. repeat until centered. The next step is to line up the first 1-2"  of the bevel with that plunge, to do that (again at an orange heat) line the plunge up with the edge and keep the ricosso parallel to the anvil face use single blows tap the bevel straight checking between strikes .  All work straightening the knife should be at the bevel angle. straightening only  the spine will twist the edge but never center it. The next step is to work down the blade straightening from heel to point, ignore everything but the section you are working on  and what you have already straightened , it will look worse before it gets better, this is normal. (swords are the absolute worst for this) pay attention to the spine as well as the edge.

If the bevel is forged all the way up to the spine (as I do) then it should straighten with the edge. You may need to shift the center of your blow around maybe centered on the blade,  or the edge, or  the spine all at the angle of the bevel depending on what need straightening. when straightening  look a the curve, support the two ends of the curve on the anvil (so there is light between the work and the anvil ) one or two blows then sight it again. it is very easy to over correct. working cooler as you get closer is good into the reds, most steels will be fine working that cold as long as you are bending not forging. 

Many times you will find the knife has a twist that is the edge appears straight and the spine appears straight  but they are not true to each other. (standing it up is a good way to catch this)  you can use the vice or a second pair of tongs and twist it straight, or forge it straight. to forge it , take a nice orange heat, from the beginning of the twist support he edge with the high side of the twist down lift the spine off the anvil slightly , and forge the bevel down along the spine. follow with another straighten cycle and it should be good. you can do the same on double edge blades only you need to forge along the center and then flip and do the same for the other two facets. 

These are really basic blacksmithing methods the same as I used in making a hook  a spoon  a door latch or ironwork just adjusted to the needs of High carbon stock. Many times when we were still building Iron work we would need to straighten heavy stock (1 1/4 sq or 3/4" /1 1/4") we would do that cold in most cases with a hand sledge (4-8lb)  the same way I just described. working one end to the other  sight, support and beat out the daylight..  

MP

Keep in mind that blade you just forged is a piece of steel. It won't get mad at you, or judge you, or think less of regardless of the method you choose to get it straight.

The whole idea is to get it into the ballpark so we can make a respectable knife out of it.

One thing I forgot to mention is that nearing the end of things - and depending on how large your anvil is - I get some color in the blade and hold it edge up along THE SIDE of the anvil so I can more easily see the cutting edge and the tip of the knife and have some good reference for that. I will even hammer/tap the knife straight while holding it along the side.

Then, swing the knife 180* so the tang is going the other direction. Take a look at it there. Doing that can help you a lot.

Posted by: @karl-b-andersen

Keep in mind that blade you just forged is a piece of steel. It won't get mad at you, or judge you, or think less of regardless of the method you choose to get it straight.

The whole idea is to get it into the ballpark so we can make a respectable knife out of it.

 

I would just like to clarify , I am not advocating for skill over a jig out of any moral or judge mental position, rather it is because mastering these kinds of things open up doors with in your work, and a reliance on finding an "easy" way will limit you. 

for instance  in straightening with a jig (any I have even seen any way , you are either straightening the spine or the edge.. but never  the two to each other..  for a shortish single edge blade you can make up for that my leaving a bit of thickness at the edge and fixing it in grinding,  forge thick grind thin so they say. but if as the blade gets longer or the cross section changes or you introduce curves or recurves ,, this becomes less and less effective.. meaning you need to leave more and more to grinding .. 

learning and mastering the basics of smithing opens doors and allows many things to be done that would not be possible other wise so I always encourage it. 

I remember several years ago I as teaching a quick intro class at ashoken, one of the guys standing around  tried to "help" one of my students,  setting up with a flatter for his bevels.. I walked over and tried to get then back to the methods I was teaching, and the guy "helping" bit  my head off saying he just wante to forge a knife.. I just walked away, a half hour latter all of the guys that listened and followed my instructions had a straight knife with centered bevels.  The other guy had a straightish blade .. offset to one side still very thick , with and indistinct ricosso but he was "done" 10 min sooner ,and it took two people to get that done.. what's he going to do in his own shop? he could fabricate a jig for the anvil , or make sure his buddy is there to help.. or just learn to do it with out a jig.. 

Working time is partly a matter of skill, mastering a skill means it will go faster. This has become a little sad for me I like the forging , it's my favorite part of making a knife ,, and the better I get the less time it takes. Even with out a power hammer I can forge a knife in 20-30 min and have it straight and ready for grinding  20 years ago it may have taken me a few hours for not as clean a result.

I get the need to speed things up when trying to make a living, and like I said I am not going to knock any one for getting a system down and jiging up to make a living, but when learning especially I think it is best to master the basics and skip the "short cuts". 

MP

Posted by: @matthew-parkinson

Posted by: @karl-b-andersen

Keep in mind that blade you just forged is a piece of steel. It won't get mad at you, or judge you, or think less of regardless of the method you choose to get it straight.

The whole idea is to get it into the ballpark so we can make a respectable knife out of it.

 

I would just like to clarify , I am not advocating for skill over a jig out of any moral or judge mental position, rather it is because mastering these kinds of things open up doors with in your work, and a reliance on finding an "easy" way will limit you. 

 

I get the need to speed things up when trying to make a living, and like I said I am not going to knock any one for getting a system down and jiging up to make a living, but when learning especially I think it is best to master the basics and skip the "short cuts". 

MP

And for me to clarify - I didn't make any mention of a jig.

I suggested using a vise which is what any good old-time blacksmith would do. That's why they had leg vises and forked tools, etc. They had to get things done to make a living and used EVERY TOOL at their disposal to move things along. 

I've now spent 53 years building things in the trade industry. At the end of the day the only thing that matters is that the job got done, and that it got done well.

We are fortunate to be in an industry where there is no right or wrong way of doing things - to a degree.

There are many ways to end up at the same destination.

Your path is yours.

While everyone is defending their opinions, let me just say that there is more than one way to skin a cat....

Every method you learn is another arrow in your quiver. Some methods are only achievable with repeated and constant practice, something not all of us have the time to accomplish. Other methods can be used on certain knives of a size range or profile shape, others are better suited for other blade types. It never hurts to know more than one way to do things.

I mostly never have a problem getting my edges centered at the anvil, even though I have never used Matthew's "whack the ricasso" method. I may have to try that, even though my brain says that will induce a twist. I may have to see Matt do it to truly understand what he means. I also have never actually used Karl's push the edge over in a vice method. I might have to try that someday as well. I often stick the blade in a vise to see if the edge is centered, but I then return to the anvil to straighten it out.

Mostly, I rely on equal forging time on both sides of the blade and working in small areas at a time. One of the things I have seen go wrong for people is they hammer on the first side and when they flip the blade over, they do not put the newly formed bevel on the anvil face. They leave it sitting on the flat portion. This will twist and disfigure the edge every time. 

I generally work on one side and get the bevel established about half as much as I want. Then I flip the blade over and lay the bevel on the anvil face and forge the second side out to where I want the edge. 

Ask two blade smiths a question, get three answers.....

A bunch of great responses here, thank you for all your time! I think a mix of everyone's methods might be great to add to my quiver for finish forging, its always fun to hear how everyone does things a bit differently!