Functional Pin Tumbler Padlock Model. User Print-To-3D: http://www.thingiverse.com/printto3d shared a very cool sectioned Paddle-Lock: http://js-kit.com/blob/sk9sIwQKzOFH1K4lciYmmQ.jpg that got me interested in making something that actually locks.
Again, all items are printable except for the springs which I removed from ball-point click pens (thankfully my wife is still putting up with disassembled pens around the house). This one is a little more complicated but it still works and makes a good desk oddity. If you were to glue the "Top", "Retainer", and "Lid" in place, the only way to get this lock open without the key would be to break it. But, what is the fun if you can't take it apart?
Note 1: I did do a bit of finish sanding on the components to make everything fit together and slide/twist well. I would suggest a "dry-fit" of the components with their mates before attempting assembly.
Note 2: The "Lock" component is a difficult print. I was able to get good results by adding two supporting features over the length and then carving/sanding it back to a circular form. If anyone has suggestions on how to print circular objects on their side, I'm all ears.
1)Print all parts
2)Setting the key
a)Insert the key into the plug.
b)Insert 5 key pins into plug.
c)With a pair of wire cutters or knife, cut the key pins to be flush with the surface of the plug. Sand as necessary.
d) Remove key and press all key pins back into the plug.
a)Cut remaining key pin short (~5mm or so).
b)Insert spring then short key pin into the side of the plug
c)While compressing the spring, insert plug into outer barrel.
d)Rotate into position to align key pins with holes for driver pins.
e)Add retaining ring at end of plug to capture the plug.
4)Inserting driver pins
a)Insert driver pins into 5 available holes. (The smaller OD goes on top and will help capture the spring)
b)Insert springs into 5 available holes.
c)Compress the front spring to be flush with the surface of the outer barrel.
d)Slide the top over the first spring and compress the next.
e)Continue until all springs are covered and top secured.
5)Adding the Lock Pins
a)Insert the Lock, lock spring, and Retainer.
b)Add the first Lock Pin so that the locking feature is vertical
c)Position it above the groves in the Plug and twist it into place. Twist away from the path to the center of the Plug for best results.
d)Repeat with the second Lock Pin. Space will be tight but the Plug can be rotated to help make this easier
e)Add the spring between the two Lock Pins.
f)Add the Lid