That drawing is most likely from a patent, and very likely done old-school style using paper, india ink pen, T-square, triangles, plus a "Leroy lettering set" to do the numbers and other annotations.
If you need to reproduce that old school look *exactly*, IMHO, the best, but not easiest way is to use the same techniques. However, it takes quite a bit of training to get good at it. If the look doesn't have to be reproduced exactly, or if you are preparing figures for an actual patent application, the best thing is to use a 3d mechanical drawing program like AutoCAD or even something like Google Sketch-up. There are plenty of on-line articles about this. Just Google {preparing figures patent application} and you will find countless articles like:
http://www.nolo.com/legal-encyclopedia/patent-drawings-draw-own-30248.html
If none of the above sound appealing to you, and you already know PS, then you certainly can use the pen tool as Sam suggested, but it's a bit of a PITA compared to a real mechanical drawing program. Note, however, that all of the software based approaches will probably look a bit too perfect compared to the example you provided, e.g., lines won't have any slight imperfections, etc..
One final thought - I knew a guy who was good at software, but wanted the old-time look. He first produced a draft version in something like AutoCAD, and then traced the result using old-school techniques.
HTH,
Tom M