Tony, Welcome to SCF. In what format are the drawings of the parts now? If they are just line drawings, you can import the images and trace over them or use them as reference for drawing the parts. SketchUp won't turn lines in an image file (PNG, JPG, etc.) into line entities though. If you have them in a CAD file format, you can import them with SU8 Pro or if you have a DXF file you can use Honoluludesktop's DXF_In plugin.