Roman Numeral Fidget Cog Ring

3D printing an anxiety ring, trying out different materials and finding out the best way to assemble it.

1. Fusion360

2. 3D Printer or service

This is simple enough, google "fusion360 free download" and sign up using an email.

Accept all default settings and get to designing the ring!

Sketch a Circle using the Sketch tool in screenshot.

This step is actually pretty important, because this first circle will be the size of the ring itself.

Everything else is decoration.

So I would suggest knowing your ring size before doing this.

I am a size ring 9, meaning the circle diameter will be 18.9mm.

Hobby Lobby has a ring fit tool you can use for free, so you can tell how big to make it.

Once you set the first circle, sketch another center circle that is 1mm bigger than than the first.

Then select the area between them and hit ctl+e to Extrude.

I extrude by 6.2mm to make the ring a little larger

So we have a ring, but we want to make a railing system, one that allows the outer part to move.

To achieve this, I made a rail in the inner part of the ring as shown.

To add this, you have to center the blank ring in the center axis, so both sides are symmetrical (image 2)

Then create a sketch the exact same diameter as your previous circle. (mine was 19.90mm, so this will be 19.90mm), then make another circle 2mm larger than the circle you made (image 3).

Now extrude the area between these two new circles, select "symmetrical" and make it 1.15mm (a total of 2.30mm)

My roman Numeral Ring has 10 sides: I to X.

This is displayed via a 10 sided Polygon.

To make this, create an "Inscribed Polygon" and select "ok".

select "10" on the number of sides.

Make the size about 12mm in distance, totaling 24mm in total (image 2).

Now also sketch a circle of 21.5mm diameter (image 3) and extrude the distance between the polygon and this new circle. Extrude between the new circle and "symmetric" by about 2.3mm (image 4)

The reason I made the circle 21.5mm is to create a .3mm distance/clearance between the inner railing system and the outer part, so that it can rotate properly. otherwise, it gets stuck.

Now we should have two bodies, rename them to "Inner" and "Outer" to distinguish them (image 5)

The borders are meant to keep the outer part held in place.

To do this, move both bodies up so that the X-Axis is touching the lowest part of your project. In my case, I selected both with Shift+click both bodies, and moved both up by 3.1 (half of the total height of the project which is 6.2mm) (image 1)

Now we can build the lower border. Create a Sketch looking top to bottom. Sketch a 19.19mm diameter Circle (which is a diameter meant to join the inner ring part), and also sketch a new circle size 22.5mm (image 2).

Now we select the area between them and extrude by .5mm, which is just enough space to provide clearance and sturdy enough to not break. (image 3)

Were done with the first border!

The second border will be done now, by moving both objects down by -6.2mm vertically (image 4)

Repeat the same thing for this side. ensure to select "join" when extruding (image 5)

we need to ensure the inner parts make sense through an analysis. Fusion360 has just that.

To activate this, construct a plane using the "construct" tool, select "ok" and now you have a plane (image 1)

select "inspect">"section analysis" and press "ok" (image 2)

now we can see through our objects and can see the caves in between them (image 3)

This requires a repeat of something we did last step, but perhaps simpler:

1. unselect the "Inner" body (image 4), we don't need this one for now.

2. select the top part of the ring and select "sketch" to make a sketch of a circle (image 4)

3. Sketch a circle, the EXACT same size as the inner diameter of the outer ring (image 5)

4. Sketch a smaller circle, EXACTLY 1mm less than the diameter of the last circle (image 6)

5. Extrude the gab between these two circles down by -.9mm and join this extrusion (image 7), and this provides the best clearance gap so that every part can move well.

Do Steps 2 Through 5 again but on the other side

Set the inner object on and the clearance should look like this (image 8)

The two details I add to this to make it look better are: the numbers, and the filet tool to make the edges smoother.

Here's how I added the text:

1. select a surface and select "create sketch" (image 1)

2. select the surface again and select "create">"text" (image 2)

3. center the text, size 3, and type what you want to the surface, I'm going with the roman numeral "I", select "ok" (image 3)

4. select "finish sketch" and extrude by .5mm

Repeat Steps 1 through 3 for every single surface 1 through 10

1. Select the top and bottom edges, and select the "fillet" feature (image 1). fillet by one to get this curved effect (image2)

you can Fillet anything else using the same method, by clocking on the edges, but that is up to you

Anything goes at this point, make some top designs, or create something entirely new!

The biggest problem I have personally ran through this design are the following:

1. NOT making enough clearance between the objects, I had to sand down a few things. I learned that the safest distance is always between .3mm to .4mm

2. NOT making a reliable way to add the two pieces together. Even my final design, I attempted to print out horizontal line between the outer part of the ring so that it would be easier to manually cut and glue back together.

Instead I learned that the best way is to cut vertically between two number of the outer ring so I can manually glue it back together. I was waiting on this, but unfortunately, the part wont come in before the competition date, I will update when I install it this way.

Basically what I did now is the following:

i. turn off the inner ring object again (image 1)

ii. construct a vertical plane that would cut through the outer ring edge (image 2)

iii. select the vertical plane (image 3) and sketch a square only on one side of the outer ring. the size of the square doesn't matter as long as it only captures one side only, select "finish sketch" (image 4)

iv. select the square sketch and extrude to cut by .001mm. The ONLY reason we are doing this step is to help print a very small gap so that we can install it on the first piece with out issues. (image 5)

3. 3d printing this can be either paid for by a 3rd party company or at a local library. do consider that there is a difference between the material types and some may work better than others at making the movement smoother. Here are the specs I used to print this out (image 2)

The cost t make a prototype for this would be less than $20 dollars, with standard shipping included. Doing so in a public library may cost nothing, but you may be working with lesser quality materials.

THANKS FOR READING!