This is a teminal block that I designed more for a test than anything. Buried inside the object are five hex cavities for holding nuts (see the cut-away photo). During the print, the ToM is paused and five nuts are dropped into place. When the print continues the nuts are covered over except for the screw hole. The design places a single layer completely over the nut to assist the structure above, but it is easily punched through when the screws are installed. This produces a much stronger screw thread than tapping the plastic. Included is the source in Alibre Design format.This is easiest if you have the Gen-4 Interface and your firmware has been updated with jetty's interface firmware (thing 15380). Set the pause for layer at 6.350mm. Or, pause the machine manually as soon as the top layer is placed on the hold-down ears at each end. This was designed for use with #4 hardware, but it will work fine with 3mm.