What are the meanings behind the working tools of a fellowcraft?

The working tools of a Fellowcraft are the Plumb, the Square, and the Level 1. While first noted in the preceding degree as the Immovable Jewels worn by the three principal officers, in the second degree they assume a double significance as instruments placed in the craftsman's hands 13. Whereas the Apprentice's tools served only to prepare stone, the Fellowcraft uses these tools to test, build, and erect structures that will endure 1.

The Square is used to test the work of the Apprentice and prove stones ready for the builder's use 13. As a symbol, it represents virtue, morality, and fair dealing 3. It serves as the try-square of conscience, instructing the Mason to square every act and word within its right angle 13.

The Level is used to lay the horizontal courses of a wall 1. Symbolically, it signifies that Masons meet upon equal footing, undivided by rank, class, or title 2. It also represents building upon the level of time, emphasizing that opportunities once past cannot be recalled or unbuilt 1.

The Plumb is used to raise perpendicular columns 1. It admonishes the Mason to walk uprightly, straight and square with the base of life 1. Drawing on the vision recorded in the Book of Amos, the Plumb symbolizes the standard by which a Mason judges his own conduct and evaluates the work of others 1.