Mechanical drawings should be made with reference to all the processes that are required in the construction of the work, and the drawings should be responsible, not only for dimensions, but for adaptation to fitting, forging, pattern-making, moulding, and so on.
Every part laid down should have something to govern it that may be termed a “base”—some position which, if understood, will suggest size, shape and relation to other parts. Searching after a base for each and every part and detail, the draughtsman should proceed upon a regular system, continually maintaining a test of what is done.
A mechanical drawing consists chiefly of three views:
1. The plan or top view.
2. The side elevation.
3. The end elevation.
In addition to the above, drawings are used to show interior portions of the figure; these are termed “sections,” and they may be taken where any plane crosses another.
Note.—The word elevation, as applied to mechanical drawings, means simply a view; hence a side elevation is a side view, or an end elevation is an end view.
The word plan is employed in place of the word top; hence a plan view is a top view or a view looking down upon the top of the piece.
A general view means a view showing the machine put together or assembled, while a detail drawing is one containing a detail, as a part of the machine or a single piece disconnected from the other parts of the whole machine.
Penciling.
