We have adapted a number of our harpsichords with 1.5"-2" casters installed under the bottom horizontal member of the stand. Not all instrument stands have a lower cross member like this, but I created one for our 1970's Dowd, which is the gray one in the photos. The casters are permanently installed to raise the instrument only about 1/4" above the floor to allow for ease of rolling within a room or onstage. They usually still need to be put on their sides to fit through doorways, but the harpsichord prof is quite pleased with the modifications. The thin spindle leg with the 3-wheel leg caster is on a fortepiano, and needs to be moved very carefully to prevent the leg from snapping off. The 3-wheel casters do work in a pinch for the harpsichords, but they do leave the instrument about 1" off the floor, which is really too much to leave on while being used.