I have been avoiding doing fidget spinners since I figured they would be old hat by now but over the past month I have been doing Intro to Tinkercad classes and it is all the kids want to talk about and print. Of course since I don't have the ball bearings, I tried to explain it to them that it is better to have the bearing first then measure around it but they happily 3D printed ones that they could just spin using their fingers. They kinda reminded me of brass knuckles....
Coincidentally, I saw a post on Facbook highlighting how to build custom spinners. This blog has everything you will need and I am very appreciative. It took me a few tries to get the exact measurements so that the bearing would fit in snugly but not too loose as it would fall right out. My measurements for the 22mm bearing was using 2 cylinders in Tinkercad, one cylinder measures 27mm all around, 7mm high with an inner "hole" cylinder of 22.5mm all around, 7mm high. I highly recommend using Tinkercad BETA. It allows you to just type measurements in once you click on the white or black boxes.
My class structure will be as follows:
1.Search Tinkercad for something that they want to use as the design spinner....(In the above example Yoda). I'm assuming once they see mine they won't want to use any of the pre-made shapes on the right. I will explain to them that whatever they chose has to be flat. Think cookie cutters.
2. Once we copy and tinker the specific object from another user, I am going to teach them how to duplicate CNTRL + D, as the keyboard shortcut. Then we are going to grab a pre-made cylinder and stretch it out for the outer circle 27mm all around, 7mm high then duplicate it and make it smaller for the inner circle 22.5mm all around, 7mm high, and make it a hole.
3. This is a great time to teach about the align tool as I want to make sure both cylinders are selected and they will be aligned in the center using the middle black buttons (one is showing red in the picture below). If they are already aligned, the button will fade out. I can't believe I haven't used this tool more often. It is a huge time saver.
Depending on the level of proficiency in the class since we only have an hour, I might print a bunch of the locking buttons for the spinners myself to save time or I might just skip it entirely!
I am also going to show them how many tries I actually did to get the ring correct. If you are having trouble getting the ball bearing in, my suggestion was to freeze the bearing so that the metal would contract enough to squeeze it in and it will probably never ever come out again. AH SCIENCE!
Other posts on this subject:
Newton Free Library is doing them!
Athens Library has a tutorial and sample STL files.
School Library Journal presents a few creative ways to make spinners besides 3D printing.
Adafruit, one of my favorite website for tutorials and science kit purchases, has a great video of assembling the middle bearing. You need to take out the rubber in the middle and possible using rubbing alcohol to make it spin faster.
UPDATE: Make sure the silhouettes (if you do the google image silhouette search and convert into svg version) actually has some sort of bottom base that connects all the parts...as we learned the hard way with Darth Vader....If you have no idea about converting to svg, see this tutorial about hand drawing prints (just skip the drawing part and google image search a .jpg to use)