I recently acquired a vertical 4-drawer Letter-Sized hanging file cabinet. I thought it would free up so much space, seeing as I had so many bankers' boxes of files. It didn't work out that way. With file vetting, I ended up using two of the four drawers, and only partially. One advantage to my previous use of multiple individual bankers' boxes was that I could stack them differently to optimize my use of space, balancing that off with the amount of surface space that I want from the boxes, on which to put stuff.
I can probably somewhat compensate for the now-suboptimal storage by using the remaining drawers for non-files. I would need a box that can fit inside the drawers, as the their bottoms are not flat, and has openings. I thought that exploiting file drawers for non-files would be quite standard, and that there would be ready-made bins specifically for this. However, most boxes that are close to the Letter-Sized width are for storing file themselves, whereas the solution I seek is slightly less wide so that it can fit inside drawers designed for Letter-Sized files.
I'm somewhat limited in the actual hacking that can be done, since I live in a 1-bedroom apartment in a highrise. I don't have the tools and surfaces to cobble up a solution that requires woodwork, such as can be found on youtube. I've created my own custom size boxes in the past by cutting up cardboard into a pattern for folding, but a box that's big enough to make good use of a file drawer would require quite a large piece of stiff cardboard that isn't interrupted by cut-outs at the corners and edges. My past experience with this approach has been that the tape holding the box together disintegrates over time, and flakes, making a bit of a mess.
Would anyone be able to point me in the right direction toward a solution? Maybe with luck, there is a source of boxes that are meant to fit inside file drawers. As I said, I would have thought that many people would want to use excess file drawer space like this.