I built one awhile back that I use at work. Its not exactly plans, but its pretty straightforward in construction. The only points I'll make right now (little time) is that this toolbox needed to hold the IAM handbook, and the Railroad Handbook, which was required to be on-hand at all times. That is what the inside of the doors hold. The second aspect is the sloped tool holder on top of the toolbox. This holds the layout tools I use the most. It is hinged so underneath the sloped top, I can store seldom used tools. Anyway its worked so well I built its twin to use in my woodworking shop. Perhaps you could use it to make yours?