In a previous paper, popular stress concentration factor charts for shoulde
r filleted shafts in bending and tension H ere shown to be in error, and mo
re accurate solutions were published. In this paper, improved stress concen
tration factor information is presented for torsional loading, based on det
ailed finite element analyses. The new solutions agree with previous design
charts, bur cover a wider range of geometries, A concise engineering equat
ion is presented for the stress concentration factor and maximum equivalent
stress under each of three lending modes, along with another equation that
reveals the location of each maximum stress component in the fillet. it is
shown that the maximum stress locations for bending and tension loading ar
e approximately the same, but can differ significantly from the maximum tor
sional stress location. In those cases, sharp surface gradients can cause t
he maximum equivalent notch stress under combined bending/axial and torsion
al loading to be overestimated when computed based on the maximum stress co
ncentration factors for each load component. An example is used to demonstr
ate how the surface strain gradient causes the placement and size of a stra
in gage to have a strong influence on strain measurements.