Manual of Engineering Drawing is my go-to. 5th Edition is the most recent but an earlier version would be just fine as a reference for non-commercial applications.

I think that point was covered on another "thread"!

Or three!

You were lucky Graham! I ordered it, but had to cancel to undo Prime, added by vile Amazon without permission. Took me several minutes to fix and when I reordered, the book was gone. Bet it was you!

Your question gave me pause for thought. I have a random collection of old technical drawing books, long out of print and the most modern is about geometry rather than drawing standards. They're good as far as they go but the oldest tells me what colours should be used to indicate materials and dimensions in fractions, which the second oldest says are forbidden in most drawing offices. 20 years difference. They all insist on First Angle Projection, except the last which advises government work must be Third Angle. Most of the technical drawings I do in QCAD are simple enough not to matter or are just for me, but it's wise to follow the rules for anything complicated nd especially if the plan is for publication.

Self-teaching from a collection of old books is a good way of developing bad-habits. Consistency is important, and drawings that mix different styles, projections, and abbreviations are a pain. Which is why I decided to buy a modern book!

Although I still often use QCAD, it's less important now I'm into 3D-CAD because that reduces the need for 2D draughtsmanship. Objects are designed realistically in three-dimensions and, if required, the software creates 2D drawings from the model to one of the current standards supported by the package, usually a choice of ANSI, BSI/ISO, JIS, and ESKD. Still a fair amount of work to do on a 2D plan created from a 3D model, but the computer does all the basics in a blink and doesn't make silly mistakes.

High-end tools aren't worth the extra bother for trivial plans but they pay-off big time as complexity increases. I reckon about half of my workshop tasks are done with simple 'back of an envelope' drawings and less than 10% benefit strongly from 3D-CAD (in my case 3D-printing). That leaves 40% where drawings of middling complexity are done in either QCAD or 3D-CAD. Which is best for a particular job "depends".

Dave