idler shaft
noun
a shaft carrying one or more gearwheels that idles between a driver shaft and a driven shaft, usually to reverse the direction of rotation or provide different spacing of gearwheels, esp in a gearbox
Words nearby idler shaft
idle pulley,
idle time,
idle wheel,
idleness,
idler,
idler shaft,
idlesse,
idlewild,
idn,
ido,
idocrase