I work at a natural gas compression company that supplies compressors for pipeline companies. I am about to start classes working toward a mechanical engineering technology degree, and am wondering if anyone knows of any books for beginners in drafting, not so much the CAD side of it, but the pencil sketching side. For example, exercises in using the tools, how to draw basic shapes, how to correctly label measurements, etc. I am really interested in an interactive book though, that has ample exercises. Thanks.