A surgical instrument includes a body, a shaft assembly, a stapling head assembly, and a drive assembly. The shaft assembly includes an actuator. The stapling head assembly is operable to drive an annularly arranged array of staples into tissue in response to translation of the actuator along a first axis relative to the body. The drive assembly is operable to translate the actuator along the first axis. The drive assembly comprises first and second rotary members. The first rotary member is rotatable about a second axis. The second axis is non-parallel with the first axis. The second rotary member is rotatable about a third axis. The third axis is non-parallel with the first axis and non-parallel with the second axis. The first rotary member is operable to drive the second rotary member to rotate about the third axis to thereby drive the actuator along the first axis.
