Other than the practicing I'm already doing, how can I learn more about technical sketching?
Perhaps the best way to start to describe what I'm talking about is define it as the intersection of two broad and easy-to-find-information-about fields
1) Freehand sketching
2) Drafting/technical drawing
I'm not trying to draw fruit or people or things I can physically see. I'm not trying to give exact dimensions and 3 projection views, nor do I want to draw each machine part separately. I'm trying to draw things like beams and linkages and gears and nuts and bolts freehand, all put together and in design mode.
The "complete beginner" basics are already completed. I have pencils and so forth. I can draw lines, circles, ellipses, etc. What I need help with is how to draw something complicated like a gear. Or how to indicate different materials. Or how to do a cutaway/cross-section.
Obviously there are some things from each field that apply to this, but I am having trouble finding information specific to this task. Even old drafting books skip lightly over the freehand chapter and then get right into formalized drafting. Architectural sketching books seem to come closest, but that is mainly concerned with buildings (duh) not machines. A previous AskMe
elicited a reply
that seems nearly perfect
except for two problems.
1) The book is very short. Worse, it looks like the material I'm interested in is only in 2 or 3 chapters.
2) The book is not in any of the many libraries available to me.
Many different googlings yield results, but they are mainly of the "first, get some pencils" variety that peter out quickly without getting anywhere. I have found reference to various books with titles like "Freehand Technical Sketching" but there's no information beyond the title to see what's really inside and if it's worth paying money for.
Maybe no such resource exists? In which case, who are some artists and/or engineers who've figured this stuff out for themselves? Perhaps I could just look at what they do.