Shop Cups

[Avery Todd]

List,

   Does anyone know of a source of the shop cups
as used for grand piano legs to replace the wheels,
but without the spindle in the middle?
   I'm considering getting 4 to put under the legs
of our harpsichord when they have to be moved from
room to room, instead of always moving them on a
dolly.
   Thanks.

Avery