I purchased a Morespace umbrella stand (http://www.morespacestand.com) a few years ago for mounting an umbrella on a pond bridge. Worked great until the 3 screws in the wood "rotted" and came loose. The problem is remounting required drilling another hole and drilling holes makes it difficult to move as the sun shifts with the season.

I decided to see if I could make an alternative way of mounting. I have come up with two ways. The first one I tried was to simply shim the mounting plate up about an inch with a hole similar to the drilled one then screw that to the deck. But, I also tried making a place that the stand could screw directly into. That worked great also. I will provide both stl files.

You will notice a small hole drilled into the base of the stand. While working on this I noted the stand collected water and had no outlet. This is my solution.

I have made a small change to the threaded base to give a tiny bit more thread bite and make the contact more secure. If you downloaded the original and find it a little wobbly you might try this one.