When punching square, rectangle, hex or other shaped holes, use the diagonal dimension or the dimension calculated from corner to corner and not the hole size to determine if it will fit through the bore of your coupling nut.
Calculating Diagonals
Square
To calculate the diagonal dimension of a square punch, multiply the size of the punch by 1.414.
Example: a 1/2" (.500) square punch (.500 x 1.414 = .707) has a diagonal of .707.
Rectangle
To calculate the diagonal dimension of a rectangular punch, determine the square root of the sum of "W2" and L2". 
Example: A rectangular punch that measures 1/4 x 1" (.250 x 1.000) has a diagonal dimension of 1.031.
Hexagon
To calculate the diagonal dimension of a hexagonal punch, multiply the size of the punch by 1.155.
Example: a 1/2" (.500) hexagonal punch (.500 x 1.155 = .577) has a diagonal of .577.
Click here to see our chart of diagonals calculated for you
Diagonal Charts