3D Printed Combination Lock Lets You See Exactly How it Works

One of the many benefits of 3D printing is that it has basically unlimited applications in the realm of education. While instructive models are certainly not new, 3D printing makes it much easier and cheaper to create your own teaching tools on demand. Do a quick search on the web for “3D models” and the results will astound you. From models of the double helix, the structure of the DNA molecule and intricately described futuristic cities to human fetuses and velociraptor skeletons, there seems to be little that can’t be modeled and printed in 3D. Now one Instructables contributor, “Rob K” from St. Charles, Missouri, has produced a fascinating 3D model of a combination lock.

One look at the functional, 3D printed combination lock and you realize you’re fascinated, although you’d probably never thought much about the subject before. Rather than being enclosed as with a standard combination lock, however, the inner workings of Rob’s lock are fully displayed while still being operational.

According to this diligent maker, the idea was inspired by a wooden version of the standard combination lock, a project posted on the Canadian maker website, woodgears.ca. Following the same process and using the same structure as the wooden lock, Rob designed a 3D printed version.

The impetus for this project was an assignment for his 3D modeling course at the University of Central Missouri (UCMO) in Warrensburg, Missouri. Rob used Autodesk Inventor 2009 to design his lock, which was produced more to demonstrate, he explained, “how a basic combination lock works [rather] than to actually lock anything.”

The lock, which features ten parts, cost about $28 to print on a Dimension 3D printer. It’s around 4” wide, 3 ½” from front to back, and 2 ½” tall. Like standard metal combination locks, it features three rotors, a bar that drops into notches in the rotors as they are turned, and a dial. Like the wooden model, Rob’s includes a stand on which the lock components are mounted. He also painted the individual pieces of his model using metallic colors to resemble the material of the locks he’s replicating in plastic.

The finished piece is impressive in its precision. Also impressive is Rob’s video that demonstrates not only how the lock works but the process of 3D printing the parts. As for the educational possibilities where this cool 3D printed combination lock is concerned, we learned that standard combination locks don’t actually need to use the “right left right” turning process to open them — evidently, any set of rotations that align the rotors will suffice — which could eliminate some of the bafflement and frustration that often come with your first few encounters with a new combination lock.

Would you be interested in creating this crafty lock? Let us know what you think at the Instructables Maker Designs Functional 3D Printed Combination Lock forum thread at 3DPB.com.