Mandrels should be approximately what percent of the conduit size?

Mandrels should be approximately what percent of the conduit size?

• A. 60%
• B. 80%
• C. 90%
• D. 50%

Answer: (B)

Mandrels inside conduit during bending provide essential internal support to keep the inner wall from collapsing or wrinkling as the bend is formed. The diameter of the mandrel is typically set to about 80% of the conduit size. This gives enough internal support to maintain a round cross-section while still leaving clearance for the mandrel to pass through the bend and through any tooling. If the mandrel is too small, it won’t adequately prevent distortion of the inner surface; if it’s too large, it can bind, complicate insertion, or cause interference with the bend. So, about 80% of the conduit size strikes the right balance, making it the recommended choice.

Mandrels inside conduit during bending provide essential internal support to keep the inner wall from collapsing or wrinkling as the bend is formed. The diameter of the mandrel is typically set to about 80% of the conduit size. This gives enough internal support to maintain a round cross-section while still leaving clearance for the mandrel to pass through the bend and through any tooling. If the mandrel is too small, it won’t adequately prevent distortion of the inner surface; if it’s too large, it can bind, complicate insertion, or cause interference with the bend. So, about 80% of the conduit size strikes the right balance, making it the recommended choice.