  Experiments and simulations show that when an initially defect free rigid
crystal is subjected to deformation at a constant rate, irreversible plastic
flow commences at the so-called {\em yield point}. The yield point is a weak
function of the deformation rate, which is usually expressed as a power law
with an extremely small non-universal exponent. We re-analyze a representative
set of published data on nanometer sized, mostly defect free, Cu, Ni and Au
crystals in the light of a recently proposed theory of yielding based on
nucleation of stable stress-free regions inside the metastable rigid solid. The
single relation derived here, which is {\em not} a power law, explains data
covering {\em fifteen} orders of magnitude in time scales.
