Which formula is used to select the correct wrench size for a 2H heavy hex nut based on stud diameter?

The correct formula to select the appropriate wrench size for a 2H heavy hex nut based on stud diameter is derived from industry standard practices for wrench sizing, which aim to ensure that the wrench fits well and provides enough leverage for tightening or loosening heavy hex nuts.

Option B, which uses the formula (D*1.5)+1/8", effectively accounts for the stud diameter (D) and adjusts it to determine the width across the flats of the nut. This formula allows for a precise fit because it factors in the additional margin needed to account for the thickness and geometry of the heavy hex nut. The inclusion of "+1/8"" also reflects the need for a bit of clearance, ensuring that the wrench can easily engage the flats of the nut without being overly tight.

This method is commonly used by professionals in the field when dealing with heavy hex nuts, as it aligns with guidelines provided by industry standards for fastening applications. The other formulas may not provide the optimal fit or clearance necessary for heavy hex nuts, making option B the most appropriate choice for this scenario.