How to Change the Combination on a Master Thumbwheel Padlock When the Combination Change Tool is Unavailable
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A heavy duty paper clip may be used to change the combination.

The combination change tool is designed to stay in place while the combination is changed, but the paper clip needs to be held in place. If the user lets go of the paper clip while turning the dials, the dial setting at the time the user lets go gets locked in. If the user continues to turn the dials, the user may lose track of the correct combination, and not be able to reopen the lock. To protect against this happening, we suggest changing the dials one at a time, and verifying that each new number has been locked in before changing the next dial. If the number did not lock in, the user can try all 9 other positions of the dial that was being changed. One of them must open the lock.

So, here is the procedure:

1) Open the lock in the normal way. Leave the lock open with the dials set to the current combination.

2) Take the heavy duty paper clip and bend it so you can push the end into the hole on the side of the lock. (If no paper clip is available, a nail or other object with a small shaft may be substituted.) As you push the end of the paper clip into the lock, you are pushing a pin back and should feel the resistance of a spring. Push until you feel the paper clip stop. If you let up on the paper clip, you should feel the spring push it back.

3) Hold the paper clip in place (in as far as it will go)  and rotate the first dial to the new number for that position. Let go of the paper clip and verify that the lock has a new combination: the new number in the first position and the old numbers in the other positions. Verification consists of locking the lock in the normal way and opening it using the new number in the first position and old numbers in the other positions.

4) If all went well, repeat the process for another dial. Continue until all dials have been changed and the lock has the new combination.

5) If the lock didn't open, the only dial which could have changed is the dial that you just moved. Try all 9 other possible positions for that dial, leaving the other dials alone. Once the lock opens, repeat the process for changing the number for that dial.

Example: The combination is to be changed from 1750 to 5387. We open the lock the normal way by dialing 1750 and pressing in on the shackle, then letting go. We press the paper clip into the hole on the side of the lock as far as it goes, hold it in place, and move the first dial from 1 to 5. We remove the paper clip and verify that the lock opens with the combination set to 5750. If it doesn't, we try all 9 other possible first numbers, leaving the other dials set to 750. Once we find the first number, we repeat our attempt to change the first number to 5.

Having successfully changed the combination to 5750, we change the second digit to 3 and verify that the combination 5350 works. Then we change the third digit to 8 and verify that 5380 is the new combination. Finally, we change the last number to 7 and verify that 5387 is the new combination. We write down the new combination and store it in a safe, secure, place.

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