Welcome to my tutorial on how to make a real knife! I'll try to be as precise and synthetic as I can so that this won't be boring to read :)
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Where to Start
Most images I used come from this build video I published on my YouTube channel, I suggest you to watch this right away, even though I don't explain much in the video you will see all the steps and get a general idea of what we'll be talking about.
Step 2: The Knife Blank
- Trace the blade template on the steel stock, we'll talk later about what kind of steel I used and my raccomandations.
- Cut the knife blank. I have a metal cutting bandsaw so I use that, but any angle grinder with a cut off wheel or even an old hacksaw can do the job.
- Drill holes in the tang for the pins and even more holes to reduce the weight of the tang. It would have been better to drill all the holes before you actually cut the stock into the shape of the blade because it would have been easier to hold the piece in the vise for drilling. In this case was not that bad because the shape il pretty straight, but for other shaped knife it can get tricky!
Here I even forgot to drill all the weight reduction holes, I realize that while I was grinding the bevels so I went back to the drill press to remedy. :)
You can find the template I made it with cad software attatched here for free!
Step 3: Tuning Up the Knife Blank
Clean all the holes just made, use a deburring tool if you happend to have one or a simple file.
Fine Tune the shape of the blank, get to the line you draw previously and check how the knife feel in the hand. Remember to go little by little since you can always take off more but you can't put back on!
I do all grinding operation on the 2x72 belt grinder I built, you probably won't have acces to one if you are reading this so I give you some alternatives:
- Angle grinder. It's a common tool that takes off steel really fast so watch out for that! Can be used to take away the bulk of the material and then files can be used for slow and precise work.
- Bench grinder depending on how powerful it is. With a tool rest you can get pretty accurate result.
- File and elbow grease. With a couple of bastard file you can pretty much do all the grinding operation, that's how I made my very first knife, it's a lot of work but it's also very satisfying:)
Step 4: Add Bevels
First thing first scribe a line where your edge will be at the middle of the stock. You can use calipers or a drill bit that has the same thickness of the material you are using.
Again I used the belt grinder for this step, I work freehand with it, but you can make some really simple jigs to hold the blade.
While grinding keep the edge facing up, and work your way through the bevel starting from the edge: at first you want to make the bevel short, then when you almost reach the line you scribed on the edge side, start to take down the bevel until you reach your desired bevel geometry.
For those who don't have a belt grinder I suggest to make a file jig, it takes times but you can get great results! I grinded bevels like that for my first knife too :)
Remember to leave a bit of steel on the cutting edge to stay safe with the heat treatment. Thin steel heat up much quicker!
For this knife I also added a choil with a round file.
Step 5: Heat Treatment
This step depends on what type of steel you are working with. For beginner knifemaker most people suggest high carbon steels because they are forgiving with the temperatures, other kind steel will require special equipment to be heat treated.
The heat treatment consist in two steps:
To harden the steel you need to heat it up and quickly quench it, this will make it really hard (so that it will hold an edge well) but also too brittle to be used as tool. With the tempering you take away some of that hardness so that it won't shatter if you accidentaly drop it on the floor :) The quench must be done in different way depending on the steel, might be in water, oil, air or even between metal plates.
For most high carbon steel like 1095 or 1070 the heat treatment can be done like so:
- heat the steel up to 800°C - 1500°F
- quench in oil (any kind, I use vegetables oil)
- heat again to 200°C - 400°F and leave it there for 2hr
To know when you are ready to quench you can rely on two aspect.
- Curie temperature: the temperature at which materials lose their permanent magnetic properties. In other words, passed this temperature (770°C - 1418°F) a magnet won't stick anymore to steel.
- Steel color: If you can do the heat treatment when the light from the sun is not too bright you can tell the temperature of the steel by his color, following color-temperature chart.
When quenching pick up the blade from the spine and quench the edge first.
If you like me are using high carbon steel I suggest you to heat up a little the oil with a piece of hot iron before quenching so that the oil is not too cold. The ideal temperature should be around 70°C - 160°F If I'm not wrong, this is done because the properties of the oil vary with temperature, and when cold it might not be fluid enough to properly cool down the blade.
The steel I made this knife out of is 1070!
Step 6: Cleaning Up
The heat treatment process leaves scales and nasty sfuff on the blade, everybody likes different finish on knives, for this one I went for a mirror finish. To get this finish I go through the grits up to 400 on the belt grinder and then up to 800 or better 1200 by hand. A polishing wheel with fine compound will bring out the mirror finish later.
To work on the knife at this point I clamp it on piece of wood, and to help me with the sandpaper I spray some WD-40.
If you want to a mirror finish you have to do all of the work before you attach the scales or you wouldn't be able to reach well the transition between blade and handle.
Step 7: Preparing the Handle
I usually follow these steps:
- Pin Holes: Starting with only 1 scale and always securing well the piece with small C clamp and locator pins (the pin itself can be used) I drill all the needed holes.
- Shaping and finishing the top side of the scales: once they are attached to the blade it will be really hard to work them without ruining the finish of the blade.
- Gluing: I use two part epoxy and clamp everything well.
Masking tape can be used to protect the finish of the blade and excess epoxy must be cleaned with solvent and cotton swab before it cure!
For this knife I added also black fiber liners, just for aesthetic. :)
Step 8: Finishing the Handle
After the glue had a chance to dry the handle can be shaped. I use various tools as: rasp, files, belt grinder and at the end fine sandpaper.
The grit of the sandpaper depends on the type of wood you are using, for this one (zebrawood) I went up to 400.
If you use the belt grinder be sure to not overheat the pins otherwise the wood around them will burn and get black with no way of fixing it.
Step 9: Sharpening and Finishing Touches
For wooden handles I apply a couple of coat of boiled linseed oil, if the wood grain opens a bit it's better to lightly sand the handle again between oil application.
The last step is the sharpening of the blade, for that I use a wet stone sharpening jig. Be sure to do this only once your knife is completely done, we don't want to cut ourself :')
Step 10: Admire Your Work!
Thank you for reading through the end! I hope you enjoyed and had some inspiration.
Feel free to ask me anything, I'll do my best to answer ! :)
If you want to know more about some of the homemade tools I used it the video above be sure to read the video description.