On hole #16, a player noticed that the clubhead on his driver was loose. The player used a borrowed Torx wrench to repair his club. However, it later occurred to the player that he might not subsequently be allowed to use the repaired club to take a stroke.
Luckily, USGA Rule 4.1a(2) states: If a conforming club is damaged during a round, a player may have the club repaired by restoring it as nearly as possible to its condition before the damage happened, while still using the original grip, shaft and clubhead. So the player was entitled to continue making strokes with the repaired club.
However, the wording of this Rule creates a potential point of controversy. The Rule uses the phrase “damaged during a round” very deliberately, so what if the player’s clubhead was actually loose BEFORE he started the round, but he only noticed it during the round? In this case, I think the player would have to be given the benefit of the doubt and be allowed to treat the club as having been damaged during the round. But if the player knew the clubhead was loose before the round started, and only chose to tighten it during the round, then the repair procedure would most likely not be allowed under this Rule.
Note also that the Rule makes a distinction between repairing a club and altering its playing characteristics. Rule 4.1a(3) states: A player must NOT make a stroke with a club whose performance characteristics he or she deliberately changed during the round. So you can’t change your loft, reset your weights, or make any other type of change to your club during a round.
Good info Brother