Introduction: Firewood and Saw Blade Knife
This is an entry in the
Trash to Treasure
If you have a damaged saw blade, don't throw it away, turn them into useful knifes! There are many ways to go about it, but in this Instructable, I will present how you can make a simple hook knife. A hook knife is a specialized knife for carving bowls or spoons. The process is very simple and can be done in home work shop with a handful of tools. The same process can be followed to create a general purpose carving knife, just don't hook the blade. You can find more Hacks and Builds from me on my YouTube channel and on Hacknbuild.com.
Disclaimer: I am a hobbyist maker with no experience other than making a few saw blade and firewood knives for myself.
- Damaged circular saw blade
- A piece of hardwood firewood
- Copper pipe or conduit for the ferrule
- Angle Grinder
- Metal Files
- Tubing cuter or hack saw (optional)
- Map gas torch
- Toaster oven or oven
- Hatchet, machete or large knife like a cleaver
- Drill or drill press & drill bits
- Sharp chisels
- Eye protection
- Ear protection
Step 1: Draw Your Knife
- Start by sketching out your knife on a sheet of paper.
- Once you have a rough idea of what your knife will look like, you can determine the exact length of your blade.
- For the hook knife, I modeled the length of the blade using a slip of paper. I made my hook knife into a longer hook shape, which due to the length isn't very suitable for carving spoons. A shorter shape would give you the angle you need to carve the shallow bowl of a spoon.
- I made the tang (the part that sits inside the handle) as long as the cutting depth of my twist drill would allow for.
- You can create a 1:1 pattern in a vector drawing program. Inkscape is an open source vector graphics application and is excellent for this application. I am not that good at drawing this by hand, so Inkscape helps me to get the results I am looking for.
Step 2: Cut Out the Blade
Now it is time to cut out the knife blanks. I prefer to use a paper pattern glued on with some spray adhesive, but there is no reason why the pattern cannot be traced or drawn freehand.
- Cut out your pattern that you made in the previous step.
- Apply spray ahesive
- Stick it on the saw blade
I find it works best and is most comfortable for me to cut a waist level with my arms close to my body. Get some scraps of wood and put them on top of the table to set your work piece high enough so that the grinding wheel does not penetrate the surface of your table.
Cut Out Blade
- Put on you hearing and eye protection,
- Cut out the blade.
Video link: Cutting the blade
Step 3: Break Down Your Log
You have a couple different options for breaking down your log. I've found splitting the log by hand to be the simplest and easiest way.
- Divide the log up into sections. Take your hatchet, machete or splitting froe and lightly tap across each section with a mallet until you have a grid that represents how you want to divide up your stock. You'll want to leave some extra material so the rough part of the lumber can be cut away.
- Continue splitting. If you only split partially, it may be easier to keep the log standing up while you continue your work.
- Square up your chunks. You can continue using your blade to rough-shape the stock to size. You can also use a chisel to take out material where needed.
Step 4: Cut and Drill the Handles
Cut and Mark
- Take your square stock and cut it to length.
- Mark an X on the end of the stock.
- Use a punch to mark where the hole will go.
- Use a small pair of dividers to scribe a circle on to the end of your stock that's the size of your ferrule. You could also simply trace around your ferrule.
In my design, the tang is tapered so I used a few bits for the hole: an initial pilot bit, a narrower bit then a wider bit. At minimum, you will need to drill a pilot hole then drill your final hole.
Step 5: Grind the Bevel
You're now ready to grind your bevel. I used a belt grinder for this, but you could also use an angle grinder with a grinding wheel or flap disc. The bevel is only ground on the outside of the knife, so make sure to put the bevel on the side of the knife you prefer. Note: I am left handed!
I created a guide 20 degree guide block to get a consistent bevel but this step can also be done free hand. The knife was tabled to the guide block using some masking tape. I worked my way up from 120-600 grit belts.
Video Link: Grinding the bevel.
Step 6: Shaping the Hook (Optional)
If you've decided to make a hook knife rather than a carving or whittling knife you can start shaping the blade. This should be done hot, but you have a number of options on how to do it. You don't need a forge to do this per-set, but it helps to set some bricks around your torch to keep the heat in.
Shaping the Blade
I heated my blade up to bright orange, and then rounded the tip on the curved part of a steel block I am using for an anvil. This is a small blade and was done using very light taps. Another approach that might work would be to hammer it over a piece of steel pipe or round bar stock.
Video link: Shaping the blade
Step 7: Heat Treating (optional)
A saw blade is already going to be hardened, so this step isn't really necessary if you've opted not to make your carving knife into a hook knife. For heat treating, followed a simple process based on my online research:
- Heat blade to cherry red
- Quench in vegetable oiI
- Temper in a toaster oven at 400F for 4 hours
The heat of the blade and the tempering temperature depends on the type of steel you're using, but this approach worked for me.
Step 8: Shape the Handle
For shaping the handle, I used a chisel and a small carving knife. You can use other tools like a spoke shave or knife for this task. Make sure both your chisel and knife are as sharp as possible. I try to carve away from myself wherever possible.
- Make it round I started by taking down the corners so the stock so it's shaped like an octagon, then take each corner down so it's shaped like a 16-sided polygon (hexadecagon?) The point is, keep taking down the corners until you essentially end up with a round shape.
- The same process is repeated for the ferrule end. Use the outline as a guide. You can use a smaller knife here to aid
Video link: Shaping the handle
Step 9: Cut Ferrule
- Mark off a length of tubing. I left a little extra length since I would upset the ends of the pipe to add some character.
- If you're using a soft material like copper or aluminium, you can use a standard tubing cutter. If you are cutting conduit, use a hack saw or angle grinder.
- Add some character by upsetting and tapering with a hammer.
Video link: Cutting ferrule
Step 10: Cut Wedges
The hole I drilled for the tang was quite large, so I used some small wood wedges to wedge the blade in place. The wedges were created from some left over scrap form the handles. These wedges can be easily split with a chisel and then carved to shape.
Since I was going to glue everything together with epoxy, I didn't worry about getting them perfect.
Step 11: Assemble Knife
Now you have all the parts in place, it's time to assemble the knife! It might be possible to assemble the knife using only wedges, but I am not that good of a craftsman and I never plan on removing the blade.
- Mix up a small batch of epoxy
- Apply some epoxy to the outside of the handle where the ferrule will go
- Set the ferrule in place by tapping on the table. I also light tapped the back end of the handle with a mallet.
- Install the wedges
- Apply epoxy to the tang and install the blade. To set the blade, I carefully held the blade and and rapped on the end.
Video link: Assemble knife
Step 12: Finish and Enjoy
- Carve the final details into your knife.
- Apply finish: An oil based finish such as Danish oil or linseed oil is very suitable.
- Make something!
Video link: Finish and enjoy
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Can you heat the blade in a fire if you dont have a forge.
I've had steel up red hot in a fireplace. I just had a bellows, not a blower.
Yes, you can dig a trench and fill it with charcoal. You would need a blower to get the fire up to forging temperature. A hair dryer would work for that purpose. For this size of a project, the easiest way is to just use a map gas torch. They run about $40. You probably don't need to pile up bricks like I did, but it will help conserve gas.