This is OpenSCAD code to create custom drawer insets for your tool draws. The included STL files are the ones that I created for my chest, but I'd encourage you to make your own.

There are three .scad files included.

1) A nice simple example to get you started.
2) A more complex one that includes finger inserts to get those pesky bits out.
3) An example that includes a hex bit holder.

Edit: Added the master layout for the full drawer that I used to design the finished product showing the breakdown into the 8 parts.

Enjoy!