It is impossible to over-emphasize the value of properly "laying out" one's work. If his lines are wrong, the workman stands a poor chance of cutting things to fit.

The two most important rules to remember in laying out all work may be stated briefly as follows:

1. Measure, gage, and square all spaces and all lines from fixed starting points or surfaces.

The working face, the joint edge, and the end first squared are always used for these purposes by mechanics. Why? See Rules for squaring stock to dimensions, Chapter VII (Squaring Stock To Dimensions).

2. Knife lines and gage lines should be used when one wishes to do accurate work.

These lines can be felt as well as seen. Properly made, they represent the first cut as well as the lay-out of the job. There are some exceptions to this rule, e. g. bevels and chamfers should be laid out with pencil lines. Why?