You want to get it straight? This will get it straight

AVigil

AVigil

Adam Vigil working the grind
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Feb 17, 2009
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I often hang out at Trugrit in the shop while their knifemaker Jeff Mutz heat treats blades. He does a great job at straightening those blades that come not straight.

He gets calls all the time from knifemakers asking for help with their own home heat treat. He tries to talk them through it but sometimes they do not have the tools on hand to get those blades straight.

He uses plates to get those blades dead straight and has made up some plates and pins for those who need them.

These are going to save some people a lot of time on gettting them straight

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Jeff Mutz is a great guy and I've used his services a few times.

Could you show a picture of that piece of paper without the pins on them or type up the text please?

How do the plates work? It seems like the pins would work alone with a vise, right? Do you just heat the blade in the oven at 350 degrees for 5min and then just bend between the pins? I've used this method before but without the small cross pins that hold them in the vise. That's a real good idea and I'm gonna use that.
 
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This method has only ended in broken blades for me. Good luck to those of you trying it. Let us know how it works out for you.
 
i4Marc said:
This method has only ended in broken blades for me. Good luck to those of you trying it. Let us know how it works out for you.
Click to expand...

All straightening methods have ended in broken blades or still warped blades. I was hoping this would work. I think I'm going to start reheat treating them to get them straight.
 
I've had decent luck clamping the blade to a thicker straight bar of steel and then tempering. I use the vice and three bar system on annealed steel.
 
I did a shop tour of a circular saw blade manufacturer. They have a flat-die press inside their tempering oven - they squeeze each plate flat while it tempers.

I do something similar - but far less powerful - when I temper. I sandwich my knife or knives between two piece of angle iron and I put on as many clamps as I can, as tight as I can. Then I put this into the tempering oven. Sometimes I need to do it again with an overbend, but most knives come out acceptably straight with just the squeeze temper.

It looks like the plates shown in this thread are using the same concept - he uses flat plates in the oven, and then resorts to the 3-pin method when necessary. Is that correct?
 
P.Brewster said:
It looks like the plates shown in this thread are using the same concept - he uses flat plates in the oven, and then resorts to the 3-pin method when necessary. Is that correct?
Click to expand...

Yes, he puts the blade in the bars and then tempers them. They come out dead nuts straight most the time.

The pins are for those who want to use them, but the bars usually takes care of the problem.
 
I have a set of tubes I use in a vise to straighten bends sometimes right out of the quench. Once you quench and all the color is out you have a short span of time to straighten before the blade gets truly hard and brittle. if you miss this window temper the blade once 25 to 50 degrees cooler than you want your final temper to be then you can clamp the blade to angle iron with washers and c-clamps to just past straight and temper again at your final degree whether it 400 or 425 or 450 your blade should come out straight.
 
Do make sure you know your steel when doing the 3 pin method. I just snapped 2 blades post heat treat this weekend using jigs I made pretty much exactly like the picture. It was astonishing to see just how much bend it took for the AEB-L to snap- but anything less and the blade was just springing back to bowed state. Where I got into trouble was when I put the 3 pins closer together (maybe 2.5" overall instead of the 4" previously) and localized the bend to a small area. Was desperate since nothing else was working. It does seem to work well with slight bends though, but be sure to listen to "mete" and heat in the tempering oven before trying!
 
That three pin thing can be well used if you can place a small very hot flame, on the spine of the blade of the spot that the center pin is located that being the place that the bend correction is needed.
Frank
 
Generally the best advise is to remove the major warps right out of the quench with gloved hands or against a wooden notch in the vise while the blade is still over 400°F.
As soon as the temperature drops, stop and go into the oven for the first tempering cycle.
After that you can use the pins, i like keeping around 400°F with the aid of an heat gun aimed at the spine of the blade, since if the blade cools it won't work so easily. Take slowly, have a coffe if necessary, but don't rush!! repeat as necessary in small steps until straight.
 
Hello All, greetings from Slovakia. I've known several methods for straightening bent blade. All of them need to be done after tempering cycles.

1. method use three bars (pins, etc.) as described before. For good result need practice.
2. method is moderated striking with rounded hammer (meaning ball shaped, you can use ball from big gear welded to stick too) from concave side of the blade. Use flat surface to strike on. Strike it evenly over bending several times. This needs practice and reapply surface finish.
3. method (I think its best of them). You need sandblaster box. Use sandblaster gun and do blasting again from concave (hollow) side of the blade. Do blasting across the blade from spine to the edge at several points
distributed evenly over the bending. More coarse sand do faster results. Surface finish need to be done again. More fine sand results to less work to do after straightening but need more time. Need practice but
results are very good. For example my friend straightened my blade (about 2 mm
thickness) with this method in 10 sec. Thicker blades need more time, of course.

I hope it is helpfull... (sorry for poor english)
 
I must be missing something on the 3rd method. How does bead blasting the concave side help to straighten? Thanks for the tips.
Jesenius said:
Hello All, greetings from Slovakia. I've known several methods for straightening bent blade. All of them need to be done after tempering cycles.

1. method use three bars (pins, etc.) as described before. For good result need practice.
2. method is moderated striking with rounded hammer (meaning ball shaped, you can use ball from big gear welded to stick too) from concave side of the blade. Use flat surface to strike on. Strike it evenly over bending several times. This needs practice and reapply surface finish.
3. method (I think its best of them). You need sandblaster box. Use sandblaster gun and do blasting again from concave (hollow) side of the blade. Do blasting across the blade from spine to the edge at several points
distributed evenly over the bending. More coarse sand do faster results. Surface finish need to be done again. More fine sand results to less work to do after straightening but need more time. Need practice but
results are very good. For example my friend straightened my blade (about 2 mm
thickness) with this method in 10 sec. Thicker blades need more time, of course.

I hope it is helpfull... (sorry for poor english)
Click to expand...
 
It is simple. Similar to method 2 it increases surface area that bends blade to opposite direction and this results to straighten blade. I can't describe it better, sorry. :(
 
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