Rotating Slider Lock

Hello everyone,

For my first submission I decided to make a type a lock, though not just any lock. I wanted to make a lock that was as unpickable as I could make it.

The whole purpose of a lock is to prevent rotational movement of the core. There are many ways of doing this, some of you may be familiar with the common pin tumble lock that involved using pins to restrict the cores movement. You can also use sidebars, levers, wafers and a whole bunch of other things.

After going through a variety of different lock types I decided that the base of my lock would be similar to a slider lock which involves moving sliders with the key into the right place so that the side bar can retract into the lock allowing the core to rotate. Since most of the toughest mechanical locks to pick involve many methods to restrict the core I decided that just having sliders that could move up and down wasn't enough. After doing more research I came across Medeco locks that require pins to be lifted to the correct height and rotated to the correct angle so a sidebar can retract inwards to rotate. This is inspired me to create a slider pin that would be able to do the same and be able to move up and rotate making it harder for pickers to find the correct gate.

Any CAD software will do, I used Fusion 360.

My first step in making the core of my lock was to create 2D sketches of all the sides of the lock. To create a 3D sketch I offset my sketch plane which allows me to move my sketches in whichever direction I needed. Then I could extrude the sketched which means to turn the 2D sketch into 3D. By extruding into the cylinder you are able to cut into it, this is how I was able to make the holes for the sidebar, key and pins which you can see in the images.

Next we need to make the sidebars which stop the core from rotating when the correct key has not been inserted. These sidebars extend out of the core and into a notch in the housing preventing rotation of the core. When the correct key has been inserted then the pins will be lifted to the correct height and rotated by the right amount so that the sidebar can retract inwards.

To make this sidebar I once again did a simple 2D rectangle sketch and extruded it and then added teeth on one side which stick out of the sidebar. These teeth sticking out is what leads to the sidebar being too long to allow for rotation. Once these teeth are properly aligned with a true gate in the pin allowing the teeth to move further inwards and the sidebar to retract the lock can open.

Then using a slider joint I can simulate the pins movement and place the sidebar in its correct position.

Afterwards we need to make the pins. As you can see the pins have notches cut into them that allow the teeth of the sidebar to enter. One is a true gate which is deep enough to allow the entire sidebar tooth in but others are false gates that only allow a portion of the tooth in. Only when all the teeth of both sidebars are in their true gates will the sidebars have enough space to retract in and allow the core to rotate. When a tooth is in a false gate the sidebar will not have enough space to retract fully into the core so it will still stop the core rotating. These false gates however provide similar feedback as a true gate and are there to mislead lockpickers into thinking they have found the true gate.

Once again to make this pin I started with a 2D circle sketch which I extruded to make a cylinder. Then using more offset planes I sketched and cut the notches into the side of the pin. After I created a little section on the opposite side of the teeth that restricts rotation to 30 degrees clockwise and anticlockwise to prevent over rotation. Finally using planes angled at 55 degrees I cut the bottom of the pin to an edge so that a key with angled cuts can cause it to rotate. Using a cylindrical joint I can then simulate the movement of a pin when a key is inserted as well as join the pins to the core.

To get the rest of the pins I can copy the original pin and 'paste new' for each new pin. Just pasting will link the pins to each other so when one changes all of them will which we don't want since Each pin should have different true and false gates and need to be able to move independently.

The last step in making the lock is to create the outer housing which holds the core. This housing will have notches where the sidebar will sit when it is not retracted. Apart from holding the lock together the housing is there to protect the lock from brute force attacks. Usually it would be made of a strong and resistant metal like hardened steel.

The housing is quite simple and involved creating three concentric circle sketched and extruding the the sections to create the necessary shell. Then I joined the core to the housing with a revolve joint to allow the core to rotate in the housing.

I hoped you enjoyed seeing how this lock was made. I really enjoyed this project since there are so many types of locks and mechanisms you could create and it was very interesting to research the best mechanical locks out there and what makes them so hard to pick.

There are many ways to improve a lock, for one combining features from multiple locks into one is a great way to improve a lock. I could add a pin tumbler section in the middle between the slider pins to increase the difficulty by increasing the number of pins that need to be manipulated or I could change the keyway to make it an awkward shape to make it harder to insert picking tools.

Go on and have a go yourself and maybe you'll create the first truly unpickable lock.