I created the Giant Handcuff Project because I enjoy teaching people about physical security, lockpicking, and bypass techniques. Several manufacturers make a "see-through" handcuff that is great for demonstrating how handcuffs work and showing the locking mechanism and bypass techniques. However, all these products are the size of a normal handcuff. When teaching a room full of people, I wanted to have something large enough to show to the entire room at once. Since a handcuff is a fairly simple device, I was confident that, even with my noob-ish CAD skills, I could design something that would work for me.
Ummmmmm.........It's a GIANT FREAKING HANDCUFF!!!
But seriously......This is great for talks or presentations on restraints and how to bypass them. Slides and animations are great, but sometimes you just want a tactile demo to make your point to a room full of people.
- Laser cut the DXF files
- Print the 3D printed parts
- Make the spring from steel wire
- Assemble and Enjoy!
I had my pieces cut out 1/8" acrylic by a laser cutting service online. It came out a bit flimsy but still definitely useable. I would have liked to do the whole thing out of 1/4" but it was just too expensive. At very least, you may want to consider doing everything except "Bottom Part.DXF" and "Top Part.DXF" out of 1/4". This will give more room for a key or pick to demonstrate the inner workings.
One of each of the files in the DXF folder is needed with the exception of "Spring.DXF". I originally hoped that an acrylic piece could act as a spring, but it didn't seem to have enough strength in 1/8" acrylic. Perhaps if you used something thicker it would work. If you want to have the "Spring.DXF" cut to use as a template for your wire, you can. Otherwise, it is not needed for assembly.
The files in the STL folder are sized as if all pieces were cut out of 1/8" acrylic. If you use 1/4" for the middle parts or the whole thing, you will need to resize them accordingly. STEP files are included in the STP folder. One day I may get around to doing this and labeling the new STLs accordingly.
You will need five each of the "Main Hex Female.stl" and "Main Hex Male.stl" and one each of the "Lock Hex Female.stl" and "Lock Hex Male.stl". I printed these in PLA with 3 perimeters and 20% infill. No supports are needed the way they are currently oriented.
I used 302 stainless steel spring wire that is 2mm (0.078") in diameter. This can be found fairly cheaply on Amazon or Ebay. The wire needs to be bent to the shape shown in "Spring.DXF". You can either print the file full sized and use it as a template, or have the piece cut out of acrylic to use as a template. I did the latter because it was such a small piece that it didn't add much to my order for laser cutting.
That's it! It's simple to put together. The printed nuts and bolts only fit into the holes they belong in. You can refer to the "Assembled.jpg" picture if you are unsure where something goes.
Now go out and share your knowledge of how handcuffs work with your team/group/friends/hackerspace/colleauges/etc! You can use a pick to show the opening mechanism or cut down some feeler gauge stock to use as a shim.
- Key - I still need to model a 3D printable key that will operate this. You can always use a pick or a wire to demonstrate how the key operates the mechanism. I wanted to get this released, so I decided to put it out there before the key was done.
- Thicker acrylic - If someone has a large laser cutter and would donate their time and the laser's time, I'll pay for materials and shipping. I'd love to have a rock solid version of this out of 1/4" acrylic.
- Resize screws - If I can get some thicker acrylic parts, I'll resize the screws to fit and leave both versions so people have choices if they want to build it but can't resize the screws.
- Working Double Lock - You can get the double lock working now if you cut a slot on the side in the middle layer and used something long to activate it. I'd like to develop pieces that can just be assembled without any additional cutting by the end user.
- Suggestions??? - Let me know on Twitter @vitosrocco