Grinding AEB-L: Fear Not
If you make knives or are new to making knives there’s a great chance that you have scoured online forums, YouTube, and social media to find answers to questions. A lot of these questions revolve around the steel you are using, especially early on. I have found that when it comes to AEB-L and Nitro-V, they get a bad rap for warping. This isn’t to say that they can’t warp, won’t warp, or don’t warp. This is simply my take on AEB-L and Nitro-V.
I love using AEB-L and have begun using Nitro-V for my two fillet models. I have found AEB-L to be incredibly tough, take an amazing edge, and be easy enough to sharpen that you can do it at home. A note, I will sharpen anything I make if you need it sharpened. That being said, I know many out there prefer to sharpen their knives on their own, myself included.
So, to get to it. In forums it seems as if many are warning others to steer clear of AEB-L due to warping. I don’t understand why this is but I am here to tell you to fear not. Some, it seems like most, of this fear of warping is coming from “warping” during grinding. I put warping in quotes because what they are referring to is different than the warping that sets in during heat treating thin knives, or knives with thin ground edges. Yes, if you use thin stock, or grind thin, you will always run the risk of warping during heat treat.
The warping I am going to talk about is post-heat. My process with grinding AEB-L and Nitro-V is to grind completely after heat treat. You do need to be conscious of what you’re doing and manage heat so that you don’t blow through your heat treat. I do this for a few reasons. I find that when AEB-L and Nitro-V are ground pre-heat treating, they get “sticky.” It is almost as if the belt sticks to the metal and grabs on. They both also throw off some very nasty metal splinters, that will definitely embed themselves in any skin or fabric they find.
If you’ve made are getting warping during heat treat this post isn’t going to help. I am not an expert on using a carbide hammer to relieve warping, and I have not yet had warping of my AEB-L or Nitro-V during heat treating.
When post-heat treat grinding thicker stock AEB-L (think .156-.25”) I have never had an issue with “warping.” My blade length of this thickness are also in the 3-5” range. When post-heat treat grinding thinner stock (think .065-.125) there has been some “warping” of my fillet knive while grinding the bevels. I have two fillet models and they are .65” or .9” thick respectively. They are the thinnest knives I currently make and are two of the longest.
One very key point: While grinding, DUNK YOUR BLADE IN WATER LIKE YOUR BOBBING FOR APPLES!!! KEEP YOUR BLADE COOL, dip it in water more than you think is needed. Use your hands to feel if it is getting too hot. If it changes colors you’ve cooked your heat treat and steel (as you will see below). The tip is highly susceptible to this throughout, and the entire blade is the higher you go in grit. Since everyone has a different grinder setup, find what works best for you and your current set up.
Below are pictures with short descriptions beneath them:
This is the Prototype of my White Marlin Fillet with layout lines. The 90º edge will be broken with an old belt. The blade is straight.
The same knife showing the 90º corner of the edge broken and a scribe line about halfway up the length of the blade.
The first bevel grind on a fillet. I have 4 different grinds on a fillet knife, 2 per side. The front one that you see here is where I take the front half of the knife to an edge thickness of .01”. I will do one front grind fully then move to the other side. Then grind that front grind fully. I will then move to the back grinds and repeat the process. The next picture is of the same knife with the same one grind on it. I’m dunking this thing in that water bucket like my grandfather dunks his donuts in coffee!
This is the “warping” that others refer to. This is showing the knife with only one grind on it, the grind photographed in the next picture up. You can see that by grinding the right side of the blade I have released stress in the steel, causing it to “warp” to the left, where the steel is not ground and there is still stress in it. The break in the 90º edge is not enough to relieve this stress. All you have to do to relieve this warp and the stress is to grind the opposite side. Now, I free hand grind, so, when I do this, prior to touching the second side to the belt, I am using my hands to bend the blade back straight for even grinds. Once you relieve the pressure near the plunge area of the grind it will straighten back out. This “warping”, in my experience, is completely self correcting. This same thing will happen again when you grind the back half, if you do it like me. The “warp” will look worse because now it is the entire length of the blade.
If you only do one grind per side you will just need to be cognizant when switching over to the other side. Some makers prefer alternating sides, I do not, and if you are using a jig, I imagine alternating will be harder.
This is what my design will look like fully ground, with the two grinds on each side blended. I have since pushed the grind height up so that there is no flat on the bevel. You may notice the discoloration at the tip, I got it too hot on the high grits and cooked it, I re-profiled the tip and got rid of that bit. Remember Dunkaroos?? Dunk your knife in that water just like those cookies into that frosting!!!
This is a different White Marlin Fillet, but what the final product looks like.
If you’ve made it this far I hope this can help you in someway. I’ll be presently surprised if you find this post from a google search, but if you do, thanks for reading!