Excellent collection of PVC connections, weldable and threadable, I downloaded from the 3D Warehouse, which added centering on the parts to make finding them in projects.
STL (Stereolithography, filesize: 18.5 MB), OBJ (OBJ, filesize: 13.7 MB), 3DS (3D Studio, filesize: 223 KB), FBX (Autodesk FBX, filesize: 11.1 MB), IGE (IGES, filesize: 299 Bytes), MAX (Autodesk 3ds Max, filesize: 627 KB), SKP (Sketchup, filesize: 1.97 MB), OTHER (Other, filesize: 237 KB)