The capstan is a precision-machined shaft driven by a motor to pull magnetic tape past the read and write heads. It works in tandem with a rubber pinch roller that presses the tape against the shaft to prevent slipping. Maintaining a perfectly constant rotational speed is essential, as any variation in the capstan introduces wow and flutter into the audio or data signal.
Check the capstan for oxide buildup before you thread the new tape.
A dirty capstan is the leading cause of tape path alignment issues and chewed tapes.
Related terms
Pinch roller
A small rubber wheel that presses magnetic tape against a rotating metal shaft to drive it forward.
Disk drive
A mechanical storage device that reads and writes data to rotating magnetic or optical platters.
Optical drive
A hardware mechanism that reads and writes data on optical discs using laser light.