  The attractive plasmon force between two metallic walls when the
electromagnetic wave propagates through a narrow slit has been studied earlier
for parallel plates and normal incidence. In present paper the effects of
imperfect adjustment of plates and laser beam are analyzed. The change of force
for non-parallel plates is shown to be of the first order in inclination angle
when the wedge is along wave propagation and of the second order for transverse
case. The small incidence angle leads to decrease in force due to the
antisymmetric waveguide mode appearing in the slit.
