Design Handbook: Engineering Drawing and Sketching (MIT 2.007)
by Daniel Frey, David Gossard · MIT OpenCourseWare
Illustrated primer from MIT's Design and Manufacturing I course covering isometric sketching, orthographic multiview drawings and view selection, dimensioning conventions, section views, and assembly drawings. A short, free starting point before tolerancing and GD&T.
More resources on Engineering Drawing & GD&T
Technical Drawing with Engineering Graphics (15th Edition)
Comprehensive engineering graphics textbook covering sketching, orthographic projection, section and auxiliary views, dimensioning, limit and plus-minus tolerancing, an introduction to GD&T, threads and fasteners, and production working drawings. The long-standing reference text for drafting courses.
Fundamentals of Geometric Dimensioning and Tolerancing (3rd Edition)
The standard structured textbook for learning GD&T from zero to working competence, and it is regularly recommended in engineering communities. It teaches GD&T per ASME Y14.5-2009 in small, sequenced units: datums, form, orientation, position, profile and runout controls, and material condition modifiers. Each unit has worked drawing examples and review problems.
GD&T Basics: Symbols Reference and Free Training
Free reference with a page for every ASME GD&T symbol. Each page covers the tolerance zone, datum references, MMC/LMC bonus tolerance, and how the feature is inspected or gauged. Also includes a wall chart, print-reading quizzes and a true position calculator.