AH-0053

Thank you so much for placing a custom order. Updates will be provided on this page and I will also send an email to let you know when new information is added. The goal is to keep you up to date on progress, as well as hopefully provide insight on how your knife was made. As always, contact me with any questions.

Parameters:
6.5" Petty Knife
52100 High-Carbon Steel
Hidden Tang
White Oak handle

Design:

Once we have a design determined I make a wood template that I will use to make sure we are on target throughout the process. I also select and rough cut the steel bar that we will forge the knife from.

Forging:

The first step in producing a knife is forging. Forging is a process in which we heat the metal to a point that it becomes like very stiff clay. Much like water changes form based on temp, steel does as well. While water undergoes very dramatic changes from liquid to solid within a few degrees, steel changes within a much wider temperature range. Once steel reaches forging temperature we can move it with a hammer on an anvil or in a hydraulic press. Alternatively, we could just grind material off - but that wastes a lot of steel and is somewhat limiting in terms of the shapes you can achieve.

There are several ways to heat metal. Traditionally in blacksmithing, coal was used but it is very dirty and somewhat difficult to control the temperature on all parts of the steel. Propane is now widely used, as it is easy to control the flame and burns relatively cleanly with less soot. It still creates carbon monoxide and creates a lot of heat that ends up being wasted.

A few years ago I purchased an induction heater. This piece of wizardry creates a magnetic frequency in between a copper coil to vibrate the molecules in the steel to generate heat. The only thing that gets hot is the steel itself and it can attain forging temperature in a matter of seconds. This allows me to precisely control the amount of heat and where it is applied to the steel.

Forging is done be pushing metal with pressure until we get the shape and thickness we want. Then we use light blows to straighten and refine the surface.

Heat Treat:

There are a few things that need to happen to the steel in order for us to create and maintain a sharp edge. Steel that has not been heat treated or hardened is somewhat soft - for example you can bend a steel bar. If the bar were hardened, it would snap at some point. Different levels of hardness can be achieved with different steels and using different temperatures. Higher hardness means you can get the edge sharper and it will stay sharp longer. As with everything though there needs to be a balance. Higher hardness also means more brittle and more likely to chip or worse break. It is important to factor in the way the knife will be used and try to hit a target that will function best for that purpose. Kitchen knives tend to be harder than outdoor knives for this reason.

How we heat treat:

Normalizing - After forging the steel has gained a lot of internal stress from being heated, beat on and cooled, reheated, beat on and cooled, etc. To relieve some of this stress we normalize the steel. This is basically just heating the steel up and letting it slowly cool so it can reset itself.

Hardening - To increase the hardness of the steel we will basically take it to a certain temperature and then cool it quickly. The temperature and method of cooling will vary by steel and the target we are trying to hit. There are specific heat treat formulas that we can follow. For 52100 steel I like to take the blade up to 1525 degrees F and then quench it in Parks 50 oil to cool it. Parks 50 is an oil specifically designed for quenching steel. It all comes down to how quickly it pulls the heat from steel. This is a rather violent act on the steel and weird things can happen. Blades can warp, bend and even crack - especially if normalizing was not done properly. Luckily we are still straight and true.

We also file test the edge with hardness files. We want the blade to be harder than the file so the file should just skate over the steel and not bite in.

Tempering - After the dramatic hardening process the steel is extremely brittle. If dropped it could shatter similar to glass. Obviously we cannot leave it in this state and have a very useful knife. The next step is tempering to help give the steel back some strength. We do this by basically baking the blade for 2 hours at around 350-400 degrees. I like to do this twice. This gives the steel a nice balance of hardness and durability. I also overheat the tang (the part of the blade that goes inside the handle). You can see the blue coloring on this portion of the steel has "lost its temper" aka gotten too hot. This steel on the tang is essentially back to being soft or unhardened. This is preferable for the handle of the knife as it will never break or snap off and we don't need the knife to hold an edge back here.

One last look at the knife compared to the template. In the next phase we will be grinding the blade a bit to get it to more closely match the template.

Grinding:

Now it is time to refined the shape and clean things up. To start we do this with a grinder that uses abrasive belts. We start with the tang. The thing attached to the knife is called a file guide. It basically keeps us from grinding things we don't want to.

After cleaning it up on the grinder.

Adding a few notches which help keep it secure in the handle.

We finalize things with a hand file.

And the final tang, ready to attach to the handle.

The next step is to grind the blade. The grinder allows us to remove material fairly quickly, but can cause heat to build up. We have to be careful not to get the blade too hot at this point as it can lose its temper. We cool the blade with water to prevent this and try to do just a little bit with each pass. We start by establishing a nice straight edge and work each side evenly.

Once the edge is established we grind up the bevels of the blade, again working each side evenly.

Once the bevels are in I round the heel and the spine of the knife. Lots of knives have kind of sharp corners in these areas, which can make it uncomfortable to use.

The knife you picked had what is called a belt finish, meaning that the final finish is done on the grinding machine. I do a few final passes to get all the kind lines to go in the same direction. The belt finish is a little more economical but still looks nice. For some knives we continue the finishing process by hand sanding the blade, which results in a little bit finer finish but also adds significant time and some cost.

After final clean up and ready for handle phase.

Handle:

After some consideration we landed on a beautiful piece of quilted maple for the handle. Almost all the wood I used is stabilized. This is a process by which it is put under vacuum in a chamber filled with acrylic resin. All the air is sucked out of the wood over a period of several days. The vacuum is then released and acrylic resin fills all of the void pockets in the wood. You cannot see the pockets with the naked eye but this is where water and other liquids might soak into the wood. The acrylic keeps any water of fluids from penetrating deep into the wood. Wood has a tendency to expand and contract when wet then dried. This can lead to splitting over time. By stabilizing the wood we ensure that in heavy kitchen use the handle will stand up to the often wet environment.

The first step from there is to drill the tang hole for the blade to attach to the handle. I mark a few lines based on the template placement on the block of wood and start drilling.

After drilling a cavity smaller than the tang, I use files to meticulously adjust the tang hole size and angle until the knife slides in perfectly.

Once I have the blade dry fit in the handle I mark the center line that is perfectly aligned with the blade. I then square the entire block on the sander to the lines.

Once the handle is square I cut the profile of the handle on the band saw.

I now double check by reinserting the knife to make sure all the lines are looking good. Starting to look like a knife!

Next I rough in the contours of the handle on the belt sander.

Once I have a pretty symmetrical rough shape I start using hand files and sandpaper to refine the handle.

Once I have the shape sorted out I sand it with a few finer grits and throw a cost of tung oil on to see how things look. I will usually hit it with some sand paper in between a few coats of tung oil, letting it dry in between. This process will take a few days because of the dry time but as you can see the character of the grain in the wood really starts to pop.

After several coats of finish the final step is to buff the handle.

Assembly & Sharpening:

Now to the fun part. I give a final polish to the blade and prepare all the pieces.

I then assemble the knife with a special high performance hot glue. This glue is much stronger and requires a higher temperature than the hot glue you may be used to. The beauty of this glue is that it is super strong and has just enough flexibility to not 'pop' under a shock (like dropping the knife) like epoxy. It is also easy to remove the handle without damaging the knife if it ever needs to be replaced using my induction forge.

Once the knife is assembled it is time to sharpen. I use a series of Japanese wet stones to set the edge and then bring it up to razor sharp. Once done it can shave hair, glide through a piece of paper and will work well for a variety of different foods.

One final look with a down and dirty picture. The blade has a thick coating of mineral oil and beeswax that I leave to soak in and protect it from any chance of oxidation. I let it sit for a few days before wiping it down and taking the final pics that I will share once done.

Hopefully this has been a fun and educational journey!