Motor interface for parallel drive shafts within an independently rotating member

A mechanism comprising:

• a surgical instrument base;
• a surgical instrument main shaft mounted to rotate relative to the surgical instrument base and comprising a proximal end, a distal end, and a main shaft rotational axis defined between the proximal and distal ends of the surgical instrument main shaft and about which the surgical instrument main shaft rotates;
• a first drive shaft mounted inside the surgical instrument main shaft and offset from the main shaft rotational axis;
• and
• a first drive feature engaged with the first drive shaft, wherein
• a first drive feature rotational axis about which the first drive feature rotates is defined for the first drive feature and is fixed relative to the surgical instrument base as the surgical instrument main shaft rotates, and
• wherein the first drive feature rotates the first drive shaft independent of rotation of the surgical instrument main shaft.