This 15mm Camera Rail (60mm) system is made for Sony A6_00 Cameras with Smallrig Camera Cage. I get the rails on my local hardware store. 15mmx100cm so I made two 30cm rails and two 20cm rails. I may ad a lens support and a way to mount the setup on a tripod soon.

To clamp the rails in place you need: 6x M4x20 6x M4 Nuts For the battery adapter 1x M5x15 1xM5 Nut And of cause for the camera/cage 2x 1/4"x 0.5" srews. thats 13.56mm.

To press the nuts into the plastic, just pull it in with the fitting screw. For the M4 screws you may need a M4x25 for pressing the nuts into place.