How is the cylindricity symbol represented?

• A. Two vertical lines
• B. Two parallel lines at a 45 degree angle with a circle in between
• C. A semicircle
• D. A single line with arrows

Answer: (B)

The symbol for cylindricity in GD&T is represented by two parallel lines at a 45-degree angle with a circle in between them. This symbol indicates that the surface in question must conform to a cylindrical form within specified tolerances, ensuring that it is round and straight along its length. The use of two parallel lines suggests that the tolerance applies to the entire surface and must maintain a consistent cylindrical shape throughout, rather than at just individual cross-sections.

Understanding the significance of this symbol is key when assessing parts for fit and function in engineering applications. This representation visually communicates the notion of a cylinder, which is fundamental to many mechanical designs, and clarifies the dimensional requirements for manufacturing and inspection processes, ensuring proper functioning of assembled components.