Estimate the endurance strength $(\backslash ($ S$\_\{$e$\}\backslash ))$ of a $1\mathrm{.}510-$in$-$diameter $($d$)$ rod of AISI $1040$ steel having a machined finish and heat$-$treated to a tensile strength $(\backslash ($ S$\_\{$u t$\}\backslash ))$ of $108$ kpsi $,$ loaded in rotating bending. Obtain the parameters for Marin surface modification factor from Table $6-2.$

The endurance strength is

kpsi.