I make each shelf for two records but of course you can make them for a larger number.
Step 1: Cutting the Wood and Measuring and Designing the 3D Part
When you have one for the bottom and one for the top you can start measuring how big the 3D-part should be. Since a record is about 31mm this would not fit into my printer. Therefore i split them and added sort of a jigsaw end to the pieces.
Then i started to print the 3D-piece, I needed two full parts for each shelf. The part is made as thin as possible and only thicker where a screwhole is added. It is also made to fit the wooden U-piece. If anyone want the 3D file I can send it, however you must modify it to fit your U-piece..
Step 2: Assembly and Mounting
It should be quite little of the plastic shown and the most you see of the shelf is the wooden pieces.