A little while ago, I bought a large order of screws to have as inventory. I was tired of looking at the hardware store to find that they didn’t have the metric sizes I wanted, so I stocked up.

Boxes of screws. Boxes of screws.

The local supplier I use shipped me everything as a sealed bag in a cardboard box for each size. So I needed a better way to store my screws. I looked around on Amazon and found that quality storage was costly, and cheap storage was just that: cheap.

Since I have a 3D printer, I turned to Thingiverse to see if there was already a solution I could use. I found this excellent screw storage solution by Thingiverse user CaptainObvious.

Small storage system from Thingiverse. Small storage system from Thingiverse.

It met my needs perfectly, except for one tiny detail: the outer boxes didn’t stay closed well with too much weight. Before I even loaded the boxes, I had a minor spill when one of the boxes slipped. I would have preferred that it stayed closed if dropped or tilted, but it made trade-offs to print without supports that weakened the closure.

This project took me about a month of off-and-on work to complete, but I’m pretty happy with the result. The original designer hadn’t included the CAD files for the project. So I had to import the original STL, measure it, and reverse-engineer a design of my own.

My reverse-engineered CAD design. My reverse-engineered CAD design.

Once I had a design that was close to the original - and most importantly, compatible with the original system’s bins - I added my custom slide-locking mechanism.

The slide-lock itself is composed of a pair of dovetail-like rails, with a piece that slides along them.

Slide-lock design render in OnShape. Slide-lock design render in OnShape.

I spent some time thinking about how to keep the slider locked to the box once installed. I came up with some complicated ideas that included clip-together parts, screws, or glue. In the end, I decided it wasn’t worth the complexity. The slider can fall off the rail if the box is open - but is easy to replace if it does.

My slide-lock version (top), and the original design (bottom). My slide-lock version (top), and the original design (bottom).

I may add my remixed version to Thingiverse for others to use, but I think it still needs some work. The rails for the slide-lock tend to have some cosmetic issues when printed. I think it might help if they were a little bigger. But to achieve that, I may need to change the proportions of the lid and box. That would allow more room on the lid for a wider rail.