Possible Clues:

• Function of some forks
• What a certain fork is for
• Calibrating to a standard frequency
• Type of fork for a musician
• What one could be doing with a pitch fork
• What some forks are used for
• Modifying vehicle engines to improve their performance.
• Harpist's ritual
• Adjustment (which can be fine)
• Preparing to play with erotic writer, pull out