I created this adapter to add accessories to my Gladiator Shelf frame. My primary use was a camera mount that I can easily adjust up or down on the shelf. I imagine I'll make plenty of next designs utilizing this adapter. I like this one because it clicks in firmly with no wiggle or play. I also included a reversed hinge for either side of the frame. Can be used on the outer or inner edges.

Feel free to adapt and remix and I look forward to what applications you use it for! If you're inexperienced in 3d modeling like me, you can just import this into Tinkercad and fuse it to whatever you're trying to create. 

Here's the original project I created this for: https://www.printables.com/model/599818-c270-camera-stand-gladiator-shelf-mount 

Mounting my c270 camera to my gladiator shelf frame. 

Supports: recommended