  Different massive black hole mass - host galaxy scaling relations suggest
that the growth of massive black holes is entangled with the evolution of their
host galaxies. The number of measured black hole masses is still limited, and
additional measurements are necessary to understand the underlying physics of
this apparent co-evolution. We add six new black hole mass (MBH) measurements
of nearby fast rotating early-type galaxies to the known black hole mass
sample, namely NGC 584, NGC 2784, NGC 3640, NGC 4570, NGC 4281 and NGC 7049.
Our target galaxies have effective velocity dispersions ({\sigma}e) between 170
and 245 km s^(-1), and thus this work provides additional insight into the
black hole properties of intermediate-mass early-type galaxies. We combine
high-resolution adaptive-optics SINFONI data with large-scale MUSE, VIMOS and
SAURON data from ATLAS3D to derive two-dimensional stellar kinematics maps. We
then build both Jeans Anisotropic Models and axisymmetric Schwarzschild models
to measure the central black hole masses. Our Schwarzschild models provide
black hole masses which are consistent with recent MBH-{\sigma}e scaling
relations. NGC 3640 has a velocity dispersion dip and NGC 7049 a constant
velocity dispersion in the center, but we can clearly constrain their lower
black hole mass limit. We conclude our analysis with a test on NGC 4570 taking
into account a variable mass-to-light ratio (M/L) when constructing dynamical
models. When considering M/L variations linked mostly to radial changes in the
stellar metallicity, we find that the dynamically determined black hole mass
from NGC 4570 decreases by 30%. Further investigations are needed in the future
to account for the impact of radial M/L gradients on dynamical modeling.
