How do you interpret workpiece reference points and system of tolerancing?

Reference points: Think about how the part

will be made, and how it will be inspected. Usually something will

make sense. Try to keep common references between drawing views,

and if possible try to base everything from points, planes, or

edges that appear in multiple views.

Tolerances: Consider how the part will be

made- what minimum tolerances can be held on the intended equipment

and processes? What is the maximum tolerance on the individual

parts that will allow the assembly to fit together and function

properly? The right answers lie between those extremes.