I did my fair share of manual drafting as an electro-mechanical designer/drafter back in the "cold-war" days as a contractor for companies including IBM, Martin-Marietta Aerospace, Storage Technology Corp., Draper Labs, Analogic Corp. and others.
I'm a relative newbie to CAD.
I say "relative" because I don't consider the AutoCAD I used in the design of plastic injection mold cavities and inserts the '80s to be relevant today. I also used Ashlar Vellum for the Mac on my pet project, but haven't used it since I realized that the version which I had that worked wonderfully on my Mac II FX wouldn't run on my PowerPC G4 Mac.
I have just purchased a license for Rhino5 for Windows and am enjoying it immensely.

work experience:

DYMA Engineering, Inc. Drafter, assembler: Electro-Mechanical November 1974 - November 1975: PC board layout (tape on mylar), assembly drawings for audio and video mixing boards and broadcast equipment.

Electro Medical Systems Designer/Drafter: Electro-Mechanical November 1977 - September 1978: P.C. Board layout, metal casting design, back-lit panels, sheet metal chassis, silk-screen artwork originals, assembly drawings of electrosurgical generator.

Martin Marietta Aerospace Designer/Drafter: Electro-Mechanical September 1978 - December 1978: Airborne electrical cable harness group on Teleoperator Retrieval System. Electronic schematic and wiring diagrams. Pictorial illustration. Contract assignment. (Lehigh Design)

Storage Technology Corp. Designer/Drafter: Electro-Mechanical February 1979 - June 1979: Computer hardware packaging, microprocessor backpanel (wire-wrap and multilayer PWB), card cages, test fixtures, perspective illustration. Contract assignment.

IBM Corp., Office Products Division Designer/Drafter: Electro-Mechanical July 1979 - January 1980: Copier Development Optics Group on mechanisms, packaging, tolerance studies. Contract assignment. (Nelson & Johnson Engineers)

C. S. Draper Labs, Inc Designer/Drafter: Electro-Mechanical March 1980 - May 1980: Electronics packaging of inertial measurement unit for missile guidance, layout drafting of computer system packaging. Contract assignment. (Additional Technical Support, Inc)

Nixdorf Computer, Inc. Designer/Drafter: Electro-Mechanical June 1980 - July 1980: Production drawings of card cage for word processor system. Contract assignment. (Sullivan & Cogliano)

Instrumentation Labs, Inc., Pixel Division Designer/Drafter: Electro-Mechanical October 1980 - November 1980: Schematic drawings for microprocessor based product. Contract assignment.

Analogic Corp Designer/Drafter: Electro-Mechanical January 1981 - October 1981: Production and assembly drawings. Sheet metal enclosures, card cages, injection molded instrument cases, perspective illustration. Direct employment.

Central Tool & Die Designer: Plastic injection molds November 1988 - December 1988: Used AutoCAD computer software on IBM compatible computer in design of core and cavity inserts and mold bases.