I'm using this for a project on hackaday.io, a weather controlled SmartWindow, listed here: https://hackaday.io/project/4789-weather-controlled-smartwindow As such, it's very specific to my application, but I've made it available to all. At the default scaling, it should fit a 3/8" screw diameter, though your tolerance may vary, based on print quality. It also includes two hex-nut bracket holds to minimize stress on the printed part.Should print easily on most machines with tolerance < 1mm. My successful prototype was made on a Makerbot Replicator (1st gen), on medium quality via MakerWare. I recommend not using support, as the small cavities may be difficult to clear out, if unnecessary internal supports are created.