1. In pointing off a number of spaces along a line, measure them all from one starting point.

For example, do not measure part of them from one end of a board and part from the other. The piece may be too long or too short.

2. In pointing off accurate measurements, a knife or needle point should be used.

The knife point is used in the shop and the needle point in the drafting room. For rough work a pencil point will often do.

3. All thick edge rules, e. g., the carpenter's pocket rule (See Fig. 15), should be turned upon edge when used in measuring, so that the lines will run down to the work.

Some rules, e. g. the architect's scale, have thin edges to accomplish this same purpose.

Always measure in the direction intended, not at an angle to it.

For example, in measuring the length of a board, apply the rule to a long edge of the board or along a line parallel to it.

Rule.

5. In pointing off short spaces (i. e., those within the limits of the rule) do not move the rule, for with every setting of the rule errors may occur.