It's a bobbin! I have created two different types of bobbins, with 3 different ways to print them.

Its compatible with both a singer, and a baby lock. These are the only two sewing machines I have tested it on, so if anyone has any problems, just let me know in the comments!

1. Two-Part Bobbin: This one is printed in two separate parts. After printing slide the two pieces together and viola! You have yourself a bobbin. Super glue is recommended. 

2. Sideways Bobbin: This and the “Upright Bobbin” are the same design, just oriented differently. One thing to note is since I didn't have to create two parts that stick up, these two designs are able to hold more thread. The only downside to this model on the inside one wall doesn't look pretty. It still works well though with the sewing machines.

3. Upright Bobbin: This is the same design as the “Sideways Bobbin” except it's upright. This is probably my favorite of the three, the only downside being on the bottom it looks rough. I grabbed my sandpaper and smoothed it.

I hope these bobbins bring ease to your workspace!

Josiah's Sewing Collection.