AbstractThis article describes the use of the Rheovibron Model DDV‐III‐B with a parallel plate modification of the sample holders to obtain oscillatory data in the shear mode for several high density polyethylene melts. A detailed analysis of the Rheovibron to obtain the dynamic shear: moduli of polymer melts using the new sample holders is given, as well as a procedure for determining the instrument compliance and inertia parameters which must be considered in analysis of the data. Using the principle of time‐temperature superposition, the data are extended to an equivalent frequency range of 1500 rad/sec. These data are compared with those obtained using the Weis‐senberg Rheogoniometer Model R‐17 for the same polymers. It is concluded that reliable measurements for dynamic shear moduli for polymer melts using the Rheovibron Model DDV‐III‐B with the modified sample holders can be made for melts with indices of about 5 or less (i.e., zero shear viscosities of 6.0 × 104poi