Hi, What im doing: So I am designing a pendant to give to my girl friend. It will be the first thing I print on shapeways. The idea is the pendant will hold a message on a piece of paper wrapped around a pin inside. The pendant will be two parts and made of sterling silver. My CAD skills are more then adequate to produce the pendant, Im using solidworks. The problem: Im not sure what specs I should give the screw thread. So i wanted anyone's advice on the pitch, clearance and size of the thread. The nominal diameter is 4mm. The pendant is pictured both with a cross section and with out. I have read the material data sheet, but the minimum detail of 0.6mm isn't as much clarification as i would like. Any help or feedback would be appreciated as im looking forward to doing more projects through shapeways.