I've been looking for high quality racks for my DAT and Mini Disc collection and I couldn't find any that meet my requirements. The racks I found were mostly made of plastic, not big enough or too expensive. I decided to build them myself. I am still experimenting with different designs so I don't have any precise measurement or diagrams other than some rough napkin drawings. I am not a professional so I make adjustments as I go. Consider these prototypes.
4" length x 2" width x 0.25" thick dividers
Apply wood glues so the dividers don't fall off.
Use orbital sander with 80, 200 grit sandpaper.
Check to make sure that DAT and MD fits ok.
I was going to make a rotating tower originally and use the space in the middle to store a few cassette players. I gave up on that idea because it takes up too much desktop space :)
I purchased a Dewalt 15 gauge brad nailer after this project, it should look cleaner without the screw heads.
This is what it looks like mounted on the wall.
Looks consistent with the Napa Valley cassette racks I bought earlier.
Original MD albums have similar dimension as cassette tapes.
DAT on the left, blank MD disc right next to it and regular cassettes, original MD albums on the right.