Introduction: Making a Mini Survival Knife From an Old Saw Blade
Hi Instructables Community,
here is my second attempt at making a compact knife that could be used in a small survival kit or as a neck knife.
In opposite to my first attempt I tried a more conventional design but again used an old saw blade as a source material.
If the embedded video doesn't work for you, you can also use this direct link (Go check it out it is worth it ;) )
If you are interested in supporting me you can check out the last step with a few suggestions of how you can help.
Step 1: Materials & Tools
- I used an old saw blade with a thickness of approx. 3mm ( around 1/8") - The blade I used had no carbide teeth so I'm assuming that the material is a HSS (High Speed Steel) from previous tests I know that the material can be hardened.
- Short length of paracord - The length will depend on the size of your hand but I will elaborate on that later
- Tools & Consumables
- Angle grinder with:
- 1,5mm cut-off disk
- Wire brush wheel
- 40-60 grit flap sanding disks
- Angle grinder with:
- Small Bench grinder
- Cordless drill
- Set of metal files & needle files
- Various grits sand paper & glass plane
- Proxxon Mini Belt Sander
- Belt sander
- Propane Torch
Step 2: Resources
- I have attached a template in three different formats so you can scale it to the size you prefer.
- The design features:
- A relatively long edge with a straight back blade
- The top of the blade has a 90° section that creates great sparks with a ferro rod and can be used to create fine tinder shavings
- A basic line cutter that can be also used to skin an animal
- Two holes to attach lanyards, the grip extension or as attachment point points when used as a spear tip
- Pronounced finger grooves and a thumb rest for a secure grip
- A sharpening choil that should help with field sharpening
- The bevel is inspired by skandi grinds although I will try out different angles as this design evolves
Step 3: Template Preparation
- Print out your template or draw one yourself with the design you fancy.
- Cut out its rough shape
Step 4: Prepping the Material
- Use the template to give you an idea for the dimensions of the blade and trace a simple outline to your blade.
- Alternatively you can reduce the shape to a simpler geometric form that will be easier to cut out. This is what I did I used a white marker for better contrast silver would work too...on a rusty blade...or gold...whatever you have available like chalk.
Step 5: Make Sparks and Metal Dust
- Now grab your angle grinder and mount a thin cut-off disk (I prefer something in the region of 1mm - 1,5mm)
- Cut out the basic shape...there is not much too it apart from following safety rules for the work with an angle grinder of course.
Step 6: Cleaning the Material
- This step is optional but I found that especially with rusty saw blades you want to clean up the surface before gluing on the template.
- You could do this again with an angle grinder with a wire brush, sand paper or other mechanical or chemical processes but really you shouldn't get too fancy here. If you have an angle grinder just use it...
Step 7: Gluing on the Template
- Using the adhesive of your choice glue the template onto the steel. I prefer to use a simple glue stick for this but others might work just fine.
- (Tip): Put some masking tape on the steel and glue the template on that. This makes the cleanup much easier.
Step 8: Relief Cuts & Pre-shaping
- To make shaping easier you should make a number of relief cuts around the outline.
- Don't move too close to the outline though a distance of 1-2mm should be maintained.
- As you can see in the pics the thin cut-off disk makes the cuts so quickly that the steel isn't overheating at the cuts as can seen by the fact that the paper doesn't show signs of heat.
- Now remove as much material as possible. Keep the cuts straight (the relief cuts will help here) to avoid bending & shattering the disk which could ruin your day...and life...so don't bend cut-off disks!
Step 9: Rough Shaping
- Now change to the flap sanding wheel with a rough grit (e.g. 40-60) and start moving closer to the outline
- Ensure that the work piece is properly clamped down to avoid it flying through the workshop and into your legs
- Take it easy as the grinder will remove a lot of material quickly and you could ruin this build easily.
- Also avoid to grind on on spot for extended periods of time to avoid overheating the steel.
Step 10: Fine Shaping
- I did this step on a bench grinder although this is less desirable due to the shape of the wheel. If you have one I suggest you use a belt grinder for this.
- Move up to the outline in this step
Step 11: Refine the Shape
- I used my mini belt grinder/sander for this step to refine the shape in areas that I could get to with the bench grinder or where I was unhappy with the finish of the bench grinder.
- Alternatively you can refine the shape using metal files.
Step 12: Making a Line Cutter and Choil
- I decided to add a little difficulty to this design just because I wanted to try out techniques for making a line cutter and choil.
- It turned out to be much easier than I thought.
- I used a round needle file for this shape and the whole process took me just 5 to 10 minutes of filing.
Step 13: Making a Line Cutter and Choil Pt.2
- In addition to the round needle file I also used a regular metal file to clean up flat areas.
- The line cutter could be also used as a safer way to cut off clothes from an injured person as the sharp edge would point away from the body another use could be the skinning of animals in an survival situation.
Step 14: Beveling the Line Cutter
- For this step I again used a needle file and created a relatively steep chisel grind that should be very sharp and also easy to maintain.
Step 15: Marking the Center of the Blade and Prep Drilling
- Using a blue marker I painted the edge blue and used a drill bit of the same diameter to scribe a centerline in preparation for the beveling.
- I also used a center punch to mark where I wanted the holes to be drilled later. It will also be easier for the drill bit to start cutting and result in a more precise hole.
Step 16: Beveling
- For this step I chose to use the slower "old school" method of creating the bevel by hand with a file and sweat.
- This worked out surprisingly well despite the fact that I didn't take the time to create a grinding jig that would help with consistent bevels. (I think I will do this as a separate project soon)
- Maintaining a consistent angle on the entire blade without a jig and years of experience is quite difficult but in the end I got to a point where I was quite happy with the result.
Step 17: Drilling Lanyard Holes
- I decided to add two holes, one to be regularly used as a lanyard hole but also to allow for attachment options in case one would want to use the blade as an improvised spear tip.
- As for the drilling, use cutting fluid and go slow. If you have a drill press, fine this will allow for better results, a hand drill will work fine too, though.
Step 18: Refining the Bevel
- Ok I admit it, I got a bit carried away here and refined the bevel with my mini belt sander.
- The basic idea here is simply to remove the tool marks from the files.
- Sandpaper with a hard flat backing/sanding black will do this job just fine
Step 19: Cleaning Up the Edges
- In this step I once again used my mini belt sander to flatten the edges in preparation for the next step.
- A sanding block could be used for this step too.
Step 20: Flattening the Faces
- This step could have been done earlier but I prefer to do it at a later stage.
- The objective here is to make the faces of the blade flat, remove scratches and uneven spots which is quite common when working with reused/upcycled stock.
- A belt sander is an extremely good time saver here since doing this by hand can take a lot of time depending on the condition of the blade.
- If you are not sure if the any spots are missing you can paint the entire face with a marker. Give it one or two strokes with sandpaper and any high or low areas should become visible now.
Step 21: Breaking the Edges
- The idea here is to remove any burrs and sharp edges (except for the cutting edges of course) that could injure the user and make the feel more comfortable. Think of it as kind of rounding over the edges with a small bevel. If you feel like it you can also take the time to completely round over the edge here.
Step 22: Prepping for the Heat Treatment
- Get some oil, vegetable oils from your kitchen will do just fine, and pour them into a metal container.
- Next create a small box with an opening on one side with your fire bricks. (Since this was only a test at this stage I decided to only use this temporary setup)
Step 23: Heating & Quenching - Hardening
- Use a heat source that will get your steel hot enough to get to its critical temperature approx. 1335°F (724°C) (If you know what kind of steel you are working with you can get the exact temperature from technical tables. If you are working with mystery steel like I did you can test if the steel is still magnetic with a small magnet. Once the the steel is no longer magnetic quickly move over to the oil and
- Quench the blade tip first in the oil. Once the steel has lost its glow you can submerge the entire blade to cool it down.
- If the hardening was successful you can try to use a file on the blade and the file should simply skip over the blade. If the file bites into the steel however the blade didn't harden and you will have to try again.
- If the hardening was successful the blade will be very hard but also very brittle so be careful and do not drop the blade.
Step 24: Clean Up
- In preparation for the tempering you should remove the slag from the previous heat treatment as this will help with a more uniform tempering.
- I used some wet sand paper in combination with some window cleaner for this step and was able to remove the discolorations quite quickly. You are not aiming for a mirror finish here.
Step 25: Tempering
- To remove the brittleness you can put the blade in your oven and heat it to 200°C - 230°C (400°F-440°F) for 1-2 hours. Let the blade cool in the air after that and the steel should now flexible in exchange for a reduced hardness.
- Now you can get very technical with all this and if you want to get serious about knife making I recommend some further research.
Step 26: Polishing by Hand Pt.1
- As a challenge for myself I decided to attempt to polish the blade by hand and try to achieve a mirror finish
- For this I went though the grits of wet sand paper from 240 up to 1200
- I would have went higher but unfortunately I didn't have any higher grit sandpaper in the shop.
- Using window cleaner seems to work better for that plain water.
Step 27: Polishing by Hand Pt.2
- As I said in the previous step I didn't have any high grit sandpaper so I went with polishing stones of various grits to finish the surface
- To be quite honest I got to an almost mirror finish and at this stage I decided to call it finished despite some remaining scratches.
Step 28: Sharpening
- I used a sharpening stone (yes the same I used for the finish) to sharpen the blade and stropped it on a leather belt with some stropping compound
- At this stage the blade got sharp enough to shave the hair on my forearm!
- I'm however not entirely happy with the geometry because I think the edge bevel s too steep. This is something I will change in future versions of this design.
Step 29: The Flexi-handle or Grip Extension
- As you may have noticed there is only enough space for two fingers on this blade I decided to try a different approach.
- I used the lanyard hole to attach a short loop of gutted paracord. You will have to try which length fits best for you.The idea is that the paracord wraps around you pinky and ring fingers and this way stabilizing the blade.
- After some trials this seems to work quite well although I can not yet comment on how this works for extended periods of time.
Step 30: Tests & Use
- So the knife is sharp and relatively sturdy as you can see in the pics it is possible to shave with the blade or create tinder
- The use with a ferro rod reliably creates sparks for fire making
- The blade fits easily into a standard Altoids tin which leads me to the conclusion that this version was a successful test and I will continue work on it to further improve it.
Step 31: Support Me
I love to create free and open source projects and if you would like to help me to continue this you can support me!
- Watching my videos and subscribing to my YouTube channel helps me grow.
- If you feel like donating me money you can do so on my paypal firstname.lastname@example.org.
- If you like this knife or other projects that I've made you can come and check out my Etsy store and maybe purchase something.
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- I'm also working on a patreon presentation which is however not ready at this stage.
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