As you saw in the last post on mounting a deck umbrella, the hole through the railing had to be a little larger than the actual umbrella pole due to some pins used to secure the umbrella to the base:
This doesn’t seem like a huge deal, but I found that the little bit of extra play in there made cranking the umbrella up and down a little tougher, and the umbrella would rattle a bit in the extra space when it was windy. Admittedly, there are plenty of low-tech solutions (my first one was to simply wrap that section of the pipe with some Waterproof Tape), but we’ve got access to a better option: a 3D printer.
The design is pretty straight-forward; there are two halves to the mount with a lip on the top that slightly overlaps the other one so that the two parts can be wrapped around the pipe and “locked” into place:
Each half is printed separately – here I used transparent filament:
… And the finished product is a nice, clean solution to a problem that could have been solved in literally countless other ways that don’t involve 3D printing (ha!):
Edit 11/14/2014: I uploaded this part to Thingiverse. You can check it out here.