This is a support to hold terra cotta planters up off of my wooden deck rails. It has a channel inside that allows drainage from the drain holes to flow out and away from the wood.
My deck rail is a standard 1 x 6 pressure treated board. Opening on part that goes onto rail is 142mm.
I have included a 2mm thick test version if the STL file. This can be printed as a template to test the fit on your own rail before committing to printing the entire thing. If you find that it is too wide, feel free to message me. I can easily modify it to bring the inner wall in 2-3mm on each side to give it a smaller opening.
NOTE: I learned that not all terra cotta planters are created equal. I designed this for one planter and then printed two more for the second planter (which was bought at a different time). It was too narrow. I modified the file to open it up. The first one created is 133mm and the second is 141mm. This is the depth of the planter from front to back. Both STLs are posted along with a 2mm thick test STL.
I used 4 solid layers for the top and bottom shells and 3 for the sides.
Supports are needed for the channel. I set the supports to have .4mm of horizontal offset from the part to make it easy to pull out of the channel (and it is).