Most technicians are occasionally called upon to service older grands, and will from time to time encounter rocker capstans, especially in vintage European instruments. Steinway and some other American brands used this configuration for a while, but they are most commonly found in Bechstein pianos.

Regulating hammer height with this capstan can challenge one’s patience, but there is a tool made specifically for this purpose, sometimes called the “Bechstein offset screwdriver”.

The offset screwdriver for rocker capstans is about 6 1/2 inches (17 cm) long. It has a steel head about the size of a sugar cube with four short blades of tool steel inserted into it. (See photo) The blades are only 1/8” (3 mm) tall to allow access into the narrow space between the rocker capstan and the jack. They are angled in such a way that facilitates the turning of screws in tight spaces. Simply turn the screw, then roll the screwdriver between your fingers to the next blade and continue your screw adjustment. This tool is the only tool that will enable a technician to regulate rocker capstans with a minimum of effort and frustration.