Inspired by the pencil glide theory for b.c.c. metal, modified pencil glide theory for f.c.c. metal was proposed, dividing the 12 glide systems of f.c.c. metal into three groups individually composed of eight {111}〈110〉 glide systems around the principal axes X[100], Y[010] and Z[001]. These assumptions yielded two mathematical solutions Ω(3) and Ω(1). In Ω(3), from the three groups with four complete conjugated glide systems composed of, respectively, two glide systems of common 〈110〉 direction, only one group with the maximum plastic work may operate if the requirements are satisfied, otherwise glide systems in Ω(1) where one of the four conjugated glide systems is zero are activated. The model considering the 12 glide systems of f.c.c. as a whole explained many experimentally stable orientations in axisymmetric and rolling deformation. The differences between the two pencil glide theories for b.c.c. and f.c.c. are also discussed with data.