Introduction: House Key Switchblade V2

About: Computing Scientist. Creator. Designer. Imaginator.

After creating the first house key switchblade out of paper, I was content with the outcome and how well it actually functioned. Now it has been just over two years and I thought that it was about time to revisit and create a new one since the wear and tear was starting to do a number on it.

As with the first version, it was built off an idea where your house key would be placed into a housing (made of card stock paper) and with some kind of push of a button, the key would pop out exposing the teeth of the key.

You will see the design process all the way to the finished product. Hopefully this Instructable will inspire others to design and created their own version.

Step 1: Materials

These are the materials I used during this build.

- Card stock (I used 110lb heavyweight from Staples)
- Standard printer paper
- Cutting mat
- Hobby knife
- Scissors
- Pencil
- Sharpies
- Protractor
- Metal ruler
- Plastic ruler
- Scotch tape
- Super glue
- Bottle of all purpose white glue
- Tooth picks

- House key
- Regular pen springs or springs with a diameter less than 3.89 mm (May be hard to find the perfect length for them)
- Tiny spring with a diameter less than 2.16 mm (I found this spring inside a portable book light)

Step 2: Design Process (Layering)

Before I started, I had to figure out how many layers of card stock I needed so that the house key would slide freely inside the housing. It ended up being 8. I also had to figure out the number of layers of card stock I would need for the springs I was using. It was 18 for the larger springs that would launch the key, and 10 for the smaller spring that would hold the release mechanism in place.

Step 3: Design Process (Blueprint Set Up)

Next I started drawing out blueprints of what I wanted it to be like. I traced out my house key and then created around it.

I put a piece of tape on the back of my house key and place it on a piece of regular printer paper. Then I traced a copy onto the paper, making sure it was as accurate as possible.

With a ruler I mark two points that were in the middle of the traced house key. Using those two points, I drew a vertical line down the middle of the traced house key. This vertical line was used as a starting point in all my blueprints and it made sure that everything was aligned.

Step 4: Design Process (Blueprint #1)

This was the first concept design. It had a lot of complexity to it. The plan was to have two buttons on each side that you would have to press in at the same time to release the key. There was also a lot of moving pieces and overall probably wasn't to practical. I wasn't satisfied with the overall aesthetics of the design, but that's how the design was the first time.

Step 5: Design Process (Blueprint #2)

The second attempt at a design. It had the same complex mechanisms and moving parts as the first blueprint. The only thing that changed was the physical shape of design. Satisfied with the design, I went ahead and tried creating a working model. I didn't get too far as it was full of errors, so I had to scrap this one. After an unsuccessful attempt at making a working model, I had to go back to the drawing boards and somehow make it simpler and more reliable.

Step 6: Design Process (Blueprint #3 and #4)

These were a couple of brainstorms I came up with after. Again their designs made it prone to errors because I ignored the fact that the more moving parts there are, the more complicated it would become. If I tried creating a working model of either one it most likely wouldn't have worked out in the end. 

Blueprint #3 had the same mechanism concept as blueprints #1 and #2. It was a little larger and I closed off the sides where the key would sliding through. 

In Blueprint #4 I was messing around with a single sided button on this one.

Step 7: Design Process (Blueprint #5)

I started looking at how actual switchblades were designed and functioned. This is where I discovered the Halo series OFT switchblades made by Microtech. I tried to make my design look similar but it started taking its own form.

A good week of thinking and a couple of new rough sketches, I finally came up with a much simpler and a lot nicer design. It had one push button release mechanism like any real switchblade would have.

Step 8: Design Process (Blueprint #6)

This was just a revision of blueprint #5, which tried to eliminate the errors that I was able to find. The release mechanism was two magnets repelling each other, and when the top magnet was pressed down it would move out of the path of the key releasing it outwards. 

I thought that this design was good enough to make an attempt at making a working model. But when I took on making a working model, the blueprint still had errors that hindered the build from working. That was as far I got with this design when I realized that the magnet idea wasn't going to work. So I scraped that model and when back to the drawing boards once again.

Step 9: Design Process (Blueprint #7: Final Design for Version 1)

The final design concept created for version 1. The idea behind this blueprint was that instead of pushing a button, it would be simpler (in my case) to have a sliding release mechanism. The release mechanism would have a tiny spring holding it in place, so that the key would not pop out suddenly. Once the release mechanism was slid out of the keys path, the key would pop out the front.

Step 10: Design Process (Blueprint #8: Final Design for Version 2)

The final design concept created for version 2. The mechanisms are the same as the first version. Only the visual design has changed where there are windows that will be cut out which allows you to see the key moving within the housing. The measurements have also been revised so that the key would fit better inside.

Step 11: Build Process I (Part 1)

The first step in the build process was to hand draw every piece onto card stock based on the final blueprint. There are 25 pieces in total.

Here are the files for the blueprint.

Step 12: Build Process I (Part 2)

Next I started cutting the pieces out.

There are 8 layers that make up the top section. 3 layers are for covering up the main launch springs as well as giving the top some design/depth. The next 5 layer are needed so there is enough room for the launch springs to moving inside as well as finishing off the sliding release mechanism.

There are 8 layers that make up the mid-section which holds the key and the sliding release mechanism. It also adds more layers that go towards giving enough room for the launch springs.

There are 9 layers that make up the bottom section. 5 layers are needed for the same reasons as the 5 layers in the top section. The last 4 layers are needed to cover up the launch springs. The pieces are gradually getting smaller because I didn't want the working model be blocky. I wanted it to have a tiny curve so that is looked nice and it would feel better when handled in someone's hand.

Step 13: Build Process I (Part 3)

Now I had to use my exacto knife to cut out the excess pieces within each piece that I did not need. I started with cutting out the 8 layers that make up the mid-section.

Step 14: Build Process I (Part 4)

Next I continued cutting the excess pieces out for the nine layers that make up the bottom section.

Step 15: Build Process I (Part 5)

The final section that I had to cut was the eight layers that make up the top section.

Step 16: Build Process I (Part 6)

Before I started gluing the layers together, I took a couple Sharpie markers and used them where they needed to be for the visual design. You'll see later on how it all comes together.

Step 17: Build Process II (Part 1)

Now that the cutting portion of the build process is done, I can now start gluing the layers together.

I started by taking these 5 bottom layers. I took some white glue and spread it all over one layer with a toothpick and stack another layer on top of it. I continued this process with the rest of the 5 layers and put them under a heavy book and let it dry for about 24 hours.

Step 18: Build Process II (Part 2)

Next I took the 8 layers that make up the key housing and started gluing them on to the 5 bottom layers that I glued together in the previous step. Again I placed the combined layers under a heavy book and let it dry for about 24 hours.

Step 19: Build Process II (Part 3)

Before moving on, it would be a good idea to make sure the key is able to slide freely and easily inside the mid-section. If it feels tight and gravity is not making the key move by itself, then you should take your exacto knife and start shaving the inner edges of the mid-section. Also check to see if the release mechanism is able to move freely too and is not in the way of the key when it is moving into the open position.

Step 20: Build Process II (Part 4)

Next I grouped the top 5 layers into sections and I glued them together.

Step 21: Build Process II (Part 5)

I took the the first part of the top layers that I glued together in the previous step and glued it onto the top of the mid-section. The house key is now in place.

Step 22: Build Process II (Part 6)

I also got the release mechanism assembled and put into place.

Step 23: Build Process II (Part 7)

Next I took the second part of the top layer and placed it on top of the layer before.

Without gluing it down I used that part to align the cover for the release mechanism. Once that was aligned I super glued it to the rest of the release mechanism. It protects and covers up the tiny spring. I used super glue for this section to ensure that the release mechanism wouldn't break off when in use.

Step 24: Build Process II (Part 8)

I finished off the release mechanism by super gluing the final three smaller pieces on. It acts as a place where I can grip the release mechanism to move it.

Step 25: Build Process II (Part 9)

I finished the top section off by gluing the last three layers together.

Step 26: Build Process II (Part 10)

Then I took the remaining bottom layers and glued them together.

Step 27: Build Process II (Part 11)

Now it was time to put the launch springs that propel the house key in. I super glued the two springs together before I put them in.

Step 28: Build Process II (Part 12)

Then I took the last part of the bottom section and glued it on, closing everything off.

I glued a 0.4 cm strip of card stock around the border cutting openings in the strip for each opening respectively, finishing everything off.

Step 29: 3D Model

This is the 3D model of my House Key Switchblade v2 that I made using Autodesk 123D Beta 9.

If anyone does decide to print this model out for their house key, check that the measurements of your house key is compatible with this model. If not you might have to modify it a bit.

Also, the model uses regular pen springs (two if the spring isn't long enough) and a tiny spring for the release mechanism.
    - Regular pen springs or springs with a diameter less than 3.89 mm
    - Tiny spring with a diameter less than 2.16 mm (I found this spring inside a portable book light)

Note: Data exported in millimeters.

Step 30: Completion

So there you have it, I've shown all the processes that I had to go through to get the this point. Tell me what you viewers think and if you have any questions leave a comment and I'll get back to you as soon as possible.



Step 31: Videos

Here are a couple videos giving you a look around and showing it in action.

3D Printing Contest

Second Prize in the
3D Printing Contest

Epilog Challenge V

Runner Up in the
Epilog Challenge V

Craft Contest

Participated in the
Craft Contest