Possible Clues:

• Cunningly altered into a machine operator
• Put your foot down to let it be about to study a book
• Lever altered but replaced
• That's where you have to put your foot down
• Alerted about machine's pedal
• Put your foot down over this
• Foot lever powering machine
• Pedal machine that's ineptly altered
• Grindstone part
• Altered dancing that requires footwork