A few years ago I welded a weight bench for my son. The square tubing on the bench base is exposed, and sharp. I decided to use my home made 3D printer to make end caps for the bench. In the process I think I have really worked out most of my settings for Replicator, Skeinforge, and Mach 3 to produce a nice looking part. Here are some images of the process and the finished part.
Here is a video of the part being printed.
Here are some pictures of the finished product.