Making a small fixed blade knife
In this project you will be making a small fixed blade knife - blade length is restricted to a maximum of 3 inches.
In this unit you will learn about the following:
- Forge skills and techniques
- Carbon steels and how this effects the blade
- Annealing, Normalising, Hardening & Tempering
- Angle Grinding and the different wheels
- Grinding a bevel
- Filing patterns
- Fitting handles
Create a Pinterest board and collect images of fixed blade knives that have short blade lengths and are interesting to you. You should also focus on the handles - you will be making your handle from wood or polymer so focus on these materials as your handle. Please see this example board that I have created on Pinterest.
Watch the following YouTube Video that elegantly describes the process of Normalising, Hardening and Tempering Steel.
As you watch the video, answer the following questions:
- What properties does Ferrite give in carbon steel?
- What does Pearlite consist of?
- What properties does pearlite give in Carbon steel?
- How can you increase the amount of Pearlite in Carbon steel?
- What does normalising do to the grain structure carbon steel & How does this differ from "factory fresh/freshly poured & rolled" carbon steel?
- What does normalizing do to the toughness (resistance to shock) of carbon steel?
- What is quenching?
- What 2 things does quenching do to the properties of carbon steel?
- What does quenching do to the grain structure of carbon steel?
- What does tempering do to the properties of hardened steel?
- What does tempering do to the grain structure of hardened carbon steel?
- Can you harden low carbon steel?
- Draw a diagram of plain carbon steel (0.5%) showing the grain structure and labelling Ferrite & Pearlite.
Find definitions for the following words, these are terminologies that we will use frequently during this unit and it is important that you have an understanding of what these mean. I will go over each of these in detail and explain how they are useful to know.
- Martensite & Austenite
- Carbon Steel
- Knife grind
- Blade belly/Handle belly
- Clip Point/Drop Point/Tanto/Sheepfoot
- Ricasso & Plunge Line
Once you have 20+ images on Pinterest and you have a range of good ideas for some knife designs the next step is to put these ideas on paper.
Start by drawing 3 vertical lines - these lines should represent the blade length and the handle length. (Blade max length is 3" and the handle should be about as wide as your hand/approx 4")
Now start sketching 4 designs for the knives that you have in mind - the only constraint is that the blade must have a convex curve.
*Tip* - Use your wrist to pivot when sketching your lines and try to 'ghost' the line before actually drawing it - this should give you more success with drawing a smooth and consistent curve.
Below is an example of what is expected:
1. Once you have sketched your 4 initial ideas - discuss these ideas with me and your peers. Make any necessary adjustments and then recheck with me.
2. Create a wooden replica of your chosen design to see what it feels like in the hand. The handle should be ergonomic for you and the blade belly and point should be functional. Try pretending to use the wooden knife profile - how would it feel if you were trying to carve a piece of wood, or cut through something? Do you knuckles rub on the surface before the blade touches the material?
3. Modify your knife design and make a new wooden replica - how does the knife feel now? You should repeat steps 2 and 3 until you have a knife that will be functional and ergonomic to use.
1. Take a photocopy of your final design and then cut this out.
2. Mount this paper copy to a piece of carbon steel that you have forged to the thickness that you would like the spine of the knife to be.
4. Use the standard angle grinder attachment to remove the remaining material until you are about 1/16th of an inch from the profile of the knife
5. Use the belt grinder and files if necessary to remove the rest of the material so that the metal is an exact match to the designed profile of the knife.
6. Use the belt grinder to flatten both sides of the knife and to remove and debris/indents in the surfaces of the sides of the knife.
7. Mark out the grind lines for the blade
8. Use the belt grinder to create this bevel (depending on which grind you choose you may need to do this to either one side or both sides of the knife)
9. Mark out any pattern that you would like to put on the spine/handle of the knife
10. File this pattern into the metal
11. Drill holes for the pins that will run through the sides of the blade handles (there is a selection of brass rods to choose from)
12. Harden the metal by reheating it to 1050 degree centigrade (Glowing bright red) and then quenching it as quickly as possible in a bath of water or oil.
13. To reduce the brittleness, the metal is then tempered. This is done by heating it to about 250 degree centigrade for about 2 hours. The tempering should be done within an hour after hardening. Put the hardened blade in the workshops toaster oven and set the timer for 2 hours.
14. Select some blanks of wood for the handles - there is a range of different types of wood that you can choose from, please ask me if you have any questions about these.
15. Cut the profile of the handle where it will meet the blade.
16. Glue on (epoxy) one side of the wooden handle to the blade.
17. Drill holes into the glued on handle from the blade side of the knife.
18. Glue on the other side of the wooden handle making sure that it matches the other handle where it meets the blade of the knife.
19. Drill through into the newly glued on handle.
20. Glue (epoxy) the brass rods into the holes so that they run through both wooden sides and the blade.
21. Shape the handle so that it is ergonomic in your handle
22. Sand the handle with progressively finer glass paper
23. Remove any oxides from the blade and polish
24. Apply a finish to the wooden handle
25. Admire you finished knife and let the compliments roll in.