Hyperfine interactions of beta-emitting F-17 implanted in single crystals of NaF and CaF2 were studied. The nuclear magnetic moment of the I(pi) = 5/2+ state was determined with an improved precision to be \mu(F-17; I(pi) = 5/2+, T1/2 = 64.5 s\ = 4.72130 +/- 0.00025 nm. Isoscalar magnetic moments of die doubly closed shell +/- 1 nucleon nuclei around mass number 16 were derived and the effective nucleon mass in the nucleus was discussed.