A method for forming a gap (16) of a width (d) which meets selected tolerance limits includes forming sidewalls (80, 82) in a microstructure, the sidewalls defining a gap (16) therebetween. The gap has a width defined between the sidewalls. The width of the gap between the sidewalls is determined. Where the determined width of the gap is below the selected tolerance limits for the width of the gap, the sidewalls are consumed to form a gap which meets the selected tolerance limits. The gap may be incorporated in a waveguide device (10) of a microswitch (100) and selectively connect input and output waveguides (130, 132).