Make a Hidden Blade with Household Materials
A hidden blade is a knife that is housed in a casing, which it extends and contracts from in order to transition back and forth between visibility and invisibility. It is sometimes attached to the wrist in a way that conceals it from sight, as popularized by the video game "Assassin's Creed." You may opt to build a real hidden blade yourself, with items that you find around the house and items you can find at any home improvement store. Follow these instructions for how to make a hidden blade with household materials.
Steps
- Disassemble 2 dual-action (extension and contraction) switchblades.
- Unscrew all of the casing screws. Set the screws in a safe place for later use.
- Take off the casing face to reveal the inside parts of the switchblades.
- Remove the trigger (the part used to engage the extension and contraction actions), spring (be careful not to bend or stretch it), mechanism, blade rivet and blade from the casing.
- Use needle-nose pliers to pull the doors and the small springs from the narrow holes of the side chambers.
- Set all parts aside for later use. You will need them to create your real hidden blade.
- Cut the end off of 1 switchblade casing.
- Hold the casing horizontally and locate the side spring chamber hole closest to where the blade base mounts.
- Use a permanent marker to draw a line that vertically bisects the casing at the outer (nearest the casing end) edge of the hole.
- Saw the end (where the blade base mounts) off at the line you marked, using either an angle grinder or a hacksaw.
- Insert a file into the blade chamber and file away any metal shards. The real hidden blade will need to move freely inside the chamber.
- Remove the notch at the blade tip end of the switchblade casing you did not cut. Use the angle grinder to cut off the notch, resulting in a continuous straight edge for the lower blade chamber wall. Scrape any remaining metal shards out of the blade chamber using a file.
- Weld the 2 switchblade casings together to create 1 long hidden blade casing.
- Arrange the cut and uncut switchblade casings length to length, so that a blade can be inserted into 1 end of the cut casing and reach the stop end of the uncut casing. The cut end of the cut switchblade casing should meet with the blade exit end of the uncut casing.
- Cut the thick aluminum bar to the length of the combined switchblade casings, plus enough extra space at each end to attach wristbands, if you want to create an Assassins Creed wrist blade.
- Spread a cold weld compound on the entire length of the cut aluminum bar.
- Set the end-to-end switchblade casings on the aluminum bar.
- Test for proper casing alignment by inserting a blade into the casing and sliding it all the way to the end.
- Allow the cold weld compound to set according to manufacturer's instructions.
- Alter the 2 switchblade casing faces to coincide with the switchblade casings.
- Cut the end off of 1 casing face at the same place you cut its corresponding casing. Hold the face next to the casing to mark the cutting line with a permanent marker before cutting.
- Use the angle grinder to cut out the metal stopper at the end of the blade chamber on the other, longer casing face. The result should be a blade chamber that runs the entire length of the casing face in a uniform width.
- Make your blade.
- Clamp the end of a switchblade blade to the end of the other piece of aluminum flat bar. You will be using the switchblade blade as a template for your real hidden blade. The blade and the aluminum flat bar should be the same width and thickness.
- Choose a drill bit that is exactly the size of the rivet hole in the switchblade blade, and drill through the blade hole that is clamped to the aluminum flat bar to make a corresponding hole in the aluminum bar.
- Trace the blade end onto the opposite end of the aluminum bar, then use an angle grinder to cut the aluminum bar into the shape of the blade.
- Modify 1 of the switchblade mechanisms.
- Locate the ramp-shaped protrusion on 1 of the long sides of the mechanism. There will be another irregular, stair-like protrusion on the opposite side and end of the mechanism, which you will leave alone.
- Cut off the ramp-shaped protrusion so that the entire corresponding side edge is a smooth, straight line.
- Set the uncut mechanism into its appropriate position in the modified casing, then lay the cut mechanism in its place at the other end of the casing and mark the place on the end of the cut mechanism where it overlaps with the uncut piece.
- Cut off the end section of the cut mechanism that overlaps the uncut mechanism so that both mechanism pieces fit snugly, end to end, inside the hidden blade casing.
- Replace the inner parts of the casing.
- Use either your fingers or needle-nose pliers to insert the doors and small springs back into the side chamber holes in the same positioning as they were before you removed them. Only put them in the holes closest to both ends, and make sure the door notches are facing the outside edges of the casing.
- Insert the real hidden blade into its chamber. Place the blade rivet in its hole once the blade is midway down the casing shaft and leave the blade in that position.
- Set the mechanisms in place.
- Place the long spring in the casing where it belongs. Attach its hook at the base end of the casing.
- Insert the switch in its place.
- Fit the casing face that covers the spring hook in place. The loose end of the spring should be exposed. Screw the casing face to the casing.
- Stretch the other end of the spring, holding only the spring hook, to the other end of the hidden blade casing and attach in place.
- Cover the exposed casing with the other casing face and screw the 2 parts together.
- Create the trigger rod for your hidden blade.
- Drill a hole through 1 end of the aluminum rod, wide enough for the key ring.
- Hold the aluminum rod so that the end opposite of the key ring end is aligned with the switchblade trigger that is farthest from the blade opening.
- Mark where both triggers line up on the aluminum rod.
- Bend the aluminum rod where the switchblade ends, so that the rod comes up to meet your hand, where the key ring will be around your finger.
- Drill holes into both triggers, from the top outside to the inside (side facing the casing).
- Align the aluminum rod with the switchblade casing, where it will be attached to the triggers. Drill holes through the aluminum rod at both trigger marks, from top to bottom (leading into trigger holes).
- Connect the trigger rod to the hidden blade casing using self-tapping screws.
Tips
- Be sure to take appropriate safety precautions when operating power tools. Always wear safety goggles and ear plugs. When using an angle grinder, you should also wear fitted long sleeves and leather gloves, and should stand so that the disk is not facing your body.
- If you choose to make an Assassins Creed wrist blade, you may use any type of strap that will fit snugly around your wrist. Some examples of wrist strap ideas include nylon weightlifting straps, medical wrist support straps and watch bands.
Things You'll Need
- Needle-nose pliers
- Vice grip
- Screwdriver
- Angle grinder (or hacksaw)
- File
- Permanent Marker
- Drill
- Vice
- Keyring
- Aluminum rod
- 2 Aluminum flat bars, the thickness of the blade in your switchblades
- 2 Dual-action switchblades
- Cold weld compound
- Self-tapping screws
- Clamp
