I find myself thinking about different things to make throughout the day, but I only have calipers on me when I'm at home, so I'm left to a best guess. Now, with these handy little pocket calipers, that best guess just got even better! Obviously there's no way to get these as accurate as some digital calipers, but these will allow you to get very close measurements up to 50mm (width) and 40mm (depth). There is even a screw to hold your position in case you can't write your measurement down right away. Hopefully these will come in handy for makers all over.
All three pieces are already in the proper orientation for printing and nothing needs supports! Make sure you leave the right side upside down unless you plan on adding supports yourself.
Students and makers of all ages can use this project to learn how to use a pair of calipers as well as the importance of tolerances between parts. Not to mention, the importance of printing in very low layer heights and printing text vertically to preserve its quality.
It is a very simple project and even novice makers and students should be able to complete this project easily.
I printed this in just over an hour, so it has potential to be used as a classroom or maker space project. Assembly takes about 1 minute.
This is my very first thing and my entry into the #MakerEdChallenge2.
I suggest 0.1mm layer height at the most in order for the numbers to print well.
I would also recommend at least 20% infill and 3 perimeters so that they will be less likely to break on your key ring.
Print (1)Right Side, (1)Left Side, (1)Screw.
Insert the screw into the screw hole on the Right Side. Screw it all the way down in order to get the threads aligned and get any burrs broken off. Take the screw back out.
Insert the Left Side into the Right side. It can only be inserted one way.
Re-insert the screw.
To measure, pull the Right Side away from the Left Side until they are wide enough to fit around the object you want to measure. Squeeze both sides toward each other tight against your object.
Tighten the screw to hold your position.
Pull your object out and look at the numbers to get your measurement in millimeters.
To measure depth, use the stick that pokes out of the far right side.
A simple Idea, A Few Iterations, and A Really Cool Tool.
This project wasn't as difficult as some because calipers already exist. I just needed to figure out how I could adapt the way they work into a compact, portable, usable package.
I started the way all parametric models start. I sketched out a rough idea of the outline on each piece and then extruded that sketch into 3D space. From there, I thought about what sort of feature would allow me to carry these around without having to think about bringing them with me everywhere. So naturally, I decided to include a hole so that I could add it to my key ring.
Now that I knew it was going to be on a key ring, I quickly realized that at least part of it would need to be fairly thin, so in order to maintain some thickness in the majority of the piece, I just cut out a section of the left side, made it half as thick, and punched a hole in it.
I also knew that I wanted to include a way to lock the position in place because I am not always in a position where I can write down a measurement, and I know that my memory can't be trusted. So, once again borrowing from the design of exiting calipers, I added a hole to the top of the right side piece, making sure the add about 0.3-0.4mm to the diameter I wanted to account for tolerance issues with the screw later.
In order to get the threads built into the design, I sketched a 1.2mm x 1.2mm x 1.2mm triangle on a vertical plane that intersected the edge of the hole I just made and gave the outer point a 0.2mm filet. The triangle was made at 1.2mm in order to accommodate the screw threads later, which would be made at 1mm equilateral. There must be extra room for the threads to slide past each other or they will simply not fit. Next, in the same sketch, I added a vertical construction line coming from the center of the hole to represent an axis. I then used the coil tool in OnShape to remove this triangle shape from the hole as threads. The threads have a pitch of 1mm.
The rest of the modeling process was fairly straightforward, but I did end up printing 3 slightly different iterations of the design. Two were due to tolerance issues between the left and right sides fitting together. The third was to add a hole at the back of the right side to allow easier separation of the two sides.
This project was really fun and completing it was very satisfying. I can't wait to start the next one.