  We present new values for the $\bar{MS}$ masses of $b$ and $c$ quarks based
on lattice NRQCD simulations of the $\Upsilon (b\bar{b})$ and $\psi (c\bar{c})$
systems. These include three measurements of the $b$ mass based on quenched
simulations with lattice spacings ranging from 0.05fm to 0.15fm, which we find
to be largely independent of lattice spacing. In addition, we find a consistent
value from an unquenched simulation at 0.08fm.
