The negative mill tolerance value of -12.5% for seamless pipe primarily affects which dimension?

The negative mill tolerance value of -12.5% for seamless pipe primarily affects which dimension?

• A. Wall thickness
• B. Length
• C. Outer diameter
• D. Weight

Answer: (C)

Mill tolerance controls how far the finished product can deviate from its stated external size. A negative value like -12.5% means the outside diameter may be up to 12.5% smaller than nominal. The outer diameter is the external dimension most directly controlled and specified for seamless pipe, affecting fit with fittings, gaskets, and flanges, as well as the pipe’s overall cross-sectional area. Wall thickness has its own tolerances and is derived from the relation between outer and inner diameters, while length is governed by separate length tolerances. Therefore, the dimension primarily affected by this negative mill tolerance is the outer diameter.

Mill tolerance controls how far the finished product can deviate from its stated external size. A negative value like -12.5% means the outside diameter may be up to 12.5% smaller than nominal. The outer diameter is the external dimension most directly controlled and specified for seamless pipe, affecting fit with fittings, gaskets, and flanges, as well as the pipe’s overall cross-sectional area. Wall thickness has its own tolerances and is derived from the relation between outer and inner diameters, while length is governed by separate length tolerances. Therefore, the dimension primarily affected by this negative mill tolerance is the outer diameter.