Straightening a knife pre heat treat (aeb-l)

I

iticam92

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Jun 12, 2014
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I'm making some edc knives out of AEB-L about an 1/8" thick, 8" long overall. Any advice/ warnings with this steel is welcome! I cut my blank out and noticed there's pretty significant bend between the blade and handle. Trying to figure out the best way to correct that bend.

I can flatten it on my grinder- I don't have the nice surface grinding attachment- this is not perfect and takes some time. I'm anticipating doing this for the rest of the knives I make with this material.
I can maybe cold hammer it? This would be quick, but not sure if this would cause issues.

I have a forge, but not a temp controlled oven, so I'm shipping them out for HT.

Do I even need to correct it? I believe this will be plate quenched, so with any luck it will be straightened out and stay that way.

Thoughts?
 
Well that sounds fun! So if the stock has a bend on receipt is it better to bend it or grind it straight, or just scrap it??
 
Knives just warp during construction. There's really no way around it.
There are ways to minimize it; normalizing, annealing, making sure you are grinding evenly, not using AEB-L ;-)
But straighting is just a way of life amongst knife makers.
 
A.McPherson said:
Knives just warp during construction. There's really no way around it.
There are ways to minimize it; normalizing, annealing, making sure you are grinding evenly, not using AEB-L ;-)
But straighting is just a way of life amongst knife makers.
Click to expand...
I think this is a great idea :)
*Get ready for it to move on you after you've hardened it, then after you've tempered it, then during grinding*
Seriously ? Instead of fighting that *****, I'll make some knives in the meantime ??? If the knives I make are for sale, AEB-L is a waste of precious time !
 
That's what I do "in the meantime" while AEBL is straightened in a temper cycle......make more knives.

Now I have a carbide hammer, so there's that!
 
It really does not take that long to deal with warps/straightening, any bar stock can come with bends in it and it’s very easy to straighten before hardening either bending it back straight or lightly straightening at an anvil with a small hammer/mallet. Any steel can warp in the quench or cold treatment or temper, some may be more prone to movement but no steel will always stay 100% flat all the time while going through several stages of thermal shock. Some people will keep blades in plates/fixtures throughout the post hardening processes (cold treatments and tempers) and that can help minimize warping. A carbide hammer is a great way to deal with post ht warps, I can work through 50 blades in an hour and have any warps corrected. The leading cause of warps during/after grinding is uneven grinding, if you grind both sides equally the blade will likely stay straight and require very little correction. The more uneven you grind the blade the more distortion you’ll likely have to deal with. I work with a good bit of nitro-v which people say is similar to aebl in regards to warping and honestly do not find it that difficult to deal with.
 
I have a variety of hammers for straightening. But I rarely use any of them to straighten things. I do use them for a variety of metal work.
Brass hammer
Lead hammer
Lignum Vitae hammer
Steel hammers in various shapes
Carbide ball hammers in a variety of ball diameters up to 3/4"
Hard rubber hammer
Nylon hammer
UHMW hammer
Leather hammer

The hamer I use the most for straightening after quench is the wooden hammer and I have a piece of wood that fits on the anvil face.
 
Stacy E. Apelt - Bladesmith said:
I have a variety of hammers for straightening. But I rarely use any of them to straighten things. I do use them for a variety of metal work.
Brass hammer
Lead hammer
Lignum Vitae hammer
Steel hammers in various shapes
Carbide ball hammers in a variety of ball diameters up to 3/4"
Hard rubber hammer
Nylon hammer
UHMW hammer
Leather hammer

The hamer I use the most for straightening after quench is the wooden hammer and I have a piece of wood that fits on the anvil face.
Click to expand...
What style wooden hammer? Do you use it the same way as a carbide ball? Does your wood anvil cover have a convex or concave shape? Just curious, I dont have much trouble with AEB-L, but time/experience can change that.
 
Not trying to derail this thread, but I just have to share my experience with the carbide hammer.

A couple of years ago I had an AEB-L chef's knife that I profiled and heat treated (no grinding), and it had a massive bow in it. I basically said, "screw it", and have been using it as a template for chef's knives in other steels. Well, after 24 hours to let the epoxy cure for the carbide ball, I put the warped knife down on the garage floor and went to town for about 2 minutes and, well let's just say that I am STUPID STUPID STUPID for not making on of these things earlier!

Seriously, that carbide tipped hammer is a total game changer. And absolute MUST if working with thin stock AEB-L!
 
My wooden hammer is about 16oz and has a standard mallet shape head made from lignum vitae. I slightly rounded one face and the other is a flat circle. The anvil cover is maple and flat. I use them when pulling a blade from the quench that has a slight warp or twist. The wood does not suck much heat away and gives me longer to adjust things before the martensitic start at 400°F. For bigger warps and twists in long sword blades I use my Japanese straightening tool and board. I also use it in persuading a warp or twist that shows up after tempering. Photos at post #13

Blade straightening question

Just got all of my15 blades of diff shapes back from the heat treater ..all went well with the exception if 1 blade has a small warp (to be honest I expected much more) my question is this fixable? The warp is behind the plunge line not affecting the blade (the part I want heat-treated) I was...
www.bladeforums.com www.bladeforums.com
 
Stacy E. Apelt - Bladesmith said:
My wooden hammer is about 16oz and has a standard mallet shape head made from lignum vitae. I slightly rounded one face and the other is a flat circle. The anvil cover is maple and flat. I use them when pulling a blade from the quench that has a slight warp or twist. The wood does not suck much heat away and gives me longer to adjust things before the martensitic start at 400°F. For bigger warps and twists in long sword blades I use my Japanese straightening tool and board. I also use it in persuading a warp or twist that shows up after tempering. Photos at post #13

Blade straightening question

Just got all of my15 blades of diff shapes back from the heat treater ..all went well with the exception if 1 blade has a small warp (to be honest I expected much more) my question is this fixable? The warp is behind the plunge line not affecting the blade (the part I want heat-treated) I was...
www.bladeforums.com www.bladeforums.com
Click to expand...
Cool, I was mostly wondering about the mallet. Looks like you use it during ht, post quench, which I have seen in videos here and there. I don't do my own ht, so I am curious if the wood mallet has any use in straightening cold.
 
The softer hammers/mallets from wood/nylon/leather/etc. are useful when you don't want to put any tool marks on the blade and want gentle hammering.
I use them a lot on doing copper work like weathervanes and copper flowers. The ends can be shaped as needed for raising or chasing.

This reminds me that I have a box with a copper project sitting in the shop to work on. It is a potted phalaenopsis orchid with two full bloom spikes. Started it a few years back and set it aside until I had time to do all the flowers. It was going to be last winter's project buy never got around to it with the retirement and surgery. Along with that box is a second project of a single orchid bloom forged from mokume-gane. It may become a brooch. I used to make sterling and gold orchid brooches, but the current materials cost has made them hard to sell.
 
Joshua Fisher said:
It really does not take that long to deal with warps/straightening, any bar stock can come with bends in it and it’s very easy to straighten before hardening either bending it back straight or lightly straightening at an anvil with a small hammer/mallet. Any steel can warp in the quench or cold treatment or temper, some may be more prone to movement but no steel will always stay 100% flat all the time while going through several stages of thermal shock. Some people will keep blades in plates/fixtures throughout the post hardening processes (cold treatments and tempers) and that can help minimize warping. A carbide hammer is a great way to deal with post ht warps, I can work through 50 blades in an hour and have any warps corrected. The leading cause of warps during/after grinding is uneven grinding, if you grind both sides equally the blade will likely stay straight and require very little correction. The more uneven you grind the blade the more distortion you’ll likely have to deal with. I work with a good bit of nitro-v which people say is similar to aebl in regards to warping and honestly do not find it that difficult to deal with.
Click to expand...
Stuart Davenport Knives said:
Not trying to derail this thread, but I just have to share my experience with the carbide hammer.

A couple of years ago I had an AEB-L chef's knife that I profiled and heat treated (no grinding), and it had a massive bow in it. I basically said, "screw it", and have been using it as a template for chef's knives in other steels. Well, after 24 hours to let the epoxy cure for the carbide ball, I put the warped knife down on the garage floor and went to town for about 2 minutes and, well let's just say that I am STUPID STUPID STUPID for not making on of these things earlier!

Seriously, that carbide tipped hammer is a total game changer. And absolute MUST if working with thin stock AEB-L!
Click to expand...
Love the feedback. I have some 1/8" thick stock that I'm making some EDC knives with and some .094" stock I'm doing chef knives with. After reading the thread here I ordered a carbide hammer from Niroc.

The plan is to grind the blades super evenly on both sides keeping them cool while I do it. I'm expecting some warpage on one side that may be corrected when I grind the other- Is that correct? And using the carbide hammer at/ towards the end to straighten by hammering on the inside of the bend to expand it.

Did I miss anything?
 
It is quite possible that you'll have some movement during grinding. Just remember that prior to heat treat you can straighten pretty easily with a vice and your hands. Once hardened, you're limited, and the hammer really is the bees knees.

I just finished grinding this 8" chef's knife and it did not move at all once I straightened it with the hammer. But should you get a bow while grinding, then yep, you got it.

Put it on a flat surface with the bow up, the ends of the knife are bent up, to where you can twirl it like a helicopter blade. Go to town, but no need to wail on it. I choked up way high on my 16oz hammer and that light force was all it took.
 
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