In this instructable, I will show you how to make a balisong, or butterfly knife.
I am not responsible for any injuries inflicted on you or anyone else by the use of this weapon. By continuing you agree to the following:
1. You will hold me harmless
2. You will follow any state or federal laws regarding this weapon
3. If injured, you will not follow suit
Make at your own risk.
Step 1: Gather Materials
First, gather the materials.
All materials can be bought at your local hardware store.
You will need:
<12"x1"x1/8" piece of Aluminium (1x)
Bolts and nuts you want to use, plus four washers for the pivots, I use a total of six bolts for my balisong
A blade (either make one, or salvage one from another knife)
Then get your tools:
Cobalt drill bits (if you plan on using a salvaged blade)
Some taps for the bolts (optional, though they make your job much easier)
Tool oil (needed for drilling hardened steel without ruining the temper, in other words, use if you are salvaging the blade)
Sand paper (also optional, just helps in the finishing process)
Step 2: Measure
Next, you will need to measure out the handles. Place your blade on top of the aluminium so that the tip is on the edge and mark a spot approximately 1 inch (2.54cm) from the tip of the tang.
Then, using the square, draw a line from that mark to the other side of the aluminium.
After that, mark the metal at the halfway point and draw a line down the middle, again, utilizing the square for a perfectly perpendicular line.
Step 3: Cut
Vise it. Now get out your hacksaw.
Cut along the line you made first.
Now re-vise it and cut along the other line.
You should now have two pieces that are .5" wide, ~4" tall, and 1/8" deep.
Repeat steps 2-3.
Step 4: Drill
Now you need to mark a spot roughly .25" from one end of the piece and .25" from the side, so that you have a perfectly centered mark. This will be the pivot point.
Drill on that mark, making sure your hole fits your bolt loosely, but not so loose that it rattles.
Repeat for all four pieces.
Step 5: File
File around the holes so that the edge becomes rounded. Do this for all four pieces.
Step 6: Make Spacers
Now it's time to make the spacers. Get out the Aluminium and mark a line >.5" from the tip.
Cut out the spacer. Remember, aesthetics are not the goal, these won't be seen.
Make two of them.
Step 7: Drill
Drill two holes in the spacer. The holes should be .25" from the side and .25" from the end for best appearance.
Make sure your bit is exactly the same size as the screw you wish to use, you will not be putting a nut on these.
Drill two holes in each handle to match the spacers. Make sure your blade can still fit!
Repeat for the other spacer/handles.
Step 8: Prepare the Blade
To get your blade ready, get out your cobalt bits and tool oil. Vise the blade carefully under the drill. Put your cobalt bit into the drill press.
Pick spots for the two pivots, and the two tang pins.
SLOWLY drill the spots, liberally apply oil.
If you are using a salvaged blade, drill out the place where the thumb grip is. The grip should just fall off.
Wipe the blade clean.
Step 9: Sand
Now, sand the handles and clean up any marks left on them. It is a good idea to give it a brushed texture as less marks will show.
Step 10: Assembly
Gather all the parts.
Tap out the holes for the spacers, or don't, but it makes the next step much easier.
Put a screw in each hole for the spacers on one handle piece. Next put a bolt in the pivot of that same handle piece. Now put a washer on the bolt on the side that the blade will contact. Then put the blade onto the bolt. Now install the spacer. Do this by aligning the screws with the holes on the spacer, then screwing them in. Put another washer on top of the blade. Then put another handle piece on. Place it first on the pivot, then tighten the screws so that they go through both handle pieces, sandwiching the spacer in between. Put a nut over the bolt and tighten.
Now repeat for the other side.
Step 11: Add the Tang Pins
Next, find a screw/bolt/roll pin that fits the holes you drilled for the tang pins. Install them, then cut the heads off (if you are using a screw/bolt). Epoxy them in for longer lasting tang pins.
Step 12: File
Now make two small indents on the side of each handle piece. The indent should be large enough for the tang pins to fit, but deep just enough for them to hold the knife in the proper position. These are crucial. Make sure that when open the knife is straight, and when closed the knife does not poke through the handles.
Step 13: Tie Up Loose Ends
File off the heads of the screws you used to secure the spacers. Cut the pivot bolts to length. File off any rough edges. Basically, make it look and feel nice and you're done. Enjoy!
Install the latch now. The easiest way of doing this is to epoxy two rare earth/Neodymium/NdFeB magnets to the inside of the handle pieces. The other way is much harder, which is to make a T latch, I won't elaborate on that, it's just not practical.