This simple snap-lid case fits together with no additional hardware. It can also be easily scaled up in different directions for a custom fit.

Scaling
All the model parts are provided in the proper orientation for printing. The nominal case dimensions for the files provided are 32mm tall x 76mm deep x 107mm long.

Set the X and Y scale factors to adjust the height and depth of the case. The X and Y scale factors must be the same to keep the case functional. The Z axis scale factor can be set independently to adjust the length of the case.

In general, you should be able to scale up by as much as a factor of 2, but I wouldn't recommend scaling this too much smaller as you will run into tolerance issues.

Assembly
Take the case bottom and fit one end into the slot in one of the end pieces. It will slide partway in, but then you'll need to gently tap it in the rest of the way using a small mallet. Next, place the lid onto the hinge pin of the partial assembly and snap the lid closed. Lastly, place the other end cap over the other edge of the bottom piece, making sure the hinge pin goes into the hole in the lid. Tap the second end into place. It all should be a pretty snug fit.