Polishing Machine, c.1875
Maker Unknown
U.S.A.
Disks from the Shellacking Press were placed on the polishing plate and an abrasive compound was applied. The spindle, which was geared to allow it to move in an orbital pattern, was released and lowered. The offset center was placed in a hole at the rear of the disk. the machine was activated and parts were ground and polished against a cast iron or glass plate. Various grits were used to create an increasingly finer finish. While the machine was in operation, the cast iron ball at the top of the spindle applied even pressure to work. when the polishing operation was complete, the disk was placed in a strainer and dipped in alcohol, dissolving the shellac and leaving clean parts.
Purchased with Museum Acquisition Funds
1997.46.1b
Shellacking Press, c.1875
Maker Unknown
U.S.A.
Many of the components of a watch have surfaces that require a uniform mirror finish. Polishing machines such as this were used to accomplish that task. Flat unpolished pieces were placed in hot shellac on one side of the round disk. The disk was then compressed and cooled in the shellacking press, ensuring that the parts would be held secure and flush against the disk. In the case of screw polishing, screws were placed on disks with circular rows of countersunk holes, allowing only the top portion to be exposed for polishing.
Purchased with Museum Acquisition Funds
1997.46.1a