C-25 Fragmentation Grenade

Date: 3/15/18

Category: 3D Printing

I saw Rouge One in theaters and after watching it knew I had to make something from it. Since it is was a new film there was very few reference photos to go off of. But I tried my best to get it as accurate as possible, I thought it would also be a good time to test 3D printing threads.

With the few reference photos I made some sketches to get an idea of what the size should be. Then I went in to Fusion 360, my favorite free program for modeling for printing. It happens to work on Mac unlike almost every other program. It also allows for easy exports to whatever slicer you use with just a couple clicks.

When I started modeling, it took me awhile to figure out how to create the indent in the side of the grenade. I ended making a cut straight through then patterning it around. Then I created a revolve to make the inner surface.

My first model didn’t quite turn out right. At that point I hadn’t figured out how to make the indents, even though it was pretty simple. So I ended up starting over. The second time it turned out pretty much how I wanted it.

After I had created one half I added threads to a duplicate half. Before that though I decided to print a test piece to make sure the threads would work. Surprisingly, I didn’t have to add any tolerance to the threads and they fit together perfectly. It is nice that there is a built in tolerance that at least work for the 3D printer I use, which is a Ultimaker 2. I made the center piece that threaded into one half fit snugly into the other half. I glued it in after making sure everything worked properly.

These are my final models. Eventually I want to come back to this project and make it open fully in one twist like an actual grenade would. I also want to add lights, which are pretty simple for this particular project.

Printing went without any hiccups, other than when I printed out the center piece in red. Luckily that was the smallest part, and i just printed another one. I printed a new one out in black , but I still plan to sand it and paint it. That way I get a more accurate finish.