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Changing the combination of a three wheel combination lock

These instructions are intended to cover most modern three wheel locks that are key changeable.
 i.e. Sargent & Greeleaf 6720 and 6730 or LaGard 3330 locks

-A three wheel lock would have three numbers and a fourth that doesn't change, i.e.. 20-40-60 and back to 96 

-A key changeable lock would typically have a small line on the dial ring to the left of the opening index and a change key hole in the back of the lock case, usually shaped either like an arrow (sort of ) or a half moon. If this describes your lock continue.

If you are unsure of your lock type or the procedure that follows do not attempt to change the combination yourself. Call 780-465-6401 for assistance.

Failure to properly change a safe combination can result in damage to the safe or even an inability to open the safe through normal procedures. Lang Locksmiths ltd. is not responsible for any damages or loss incurred by anyone attempting this procedure. 

Before you begin you must have:

1. The existing combination to the safe

2. The change key of the appropriate type for your brand of lock

3. The safe door open with the lock in the locked condition

To change your combination:

1. Choose your new combination of three numbers and write them down. 

Typically, the dialing procedure would be:
Left to- (first #) - 4 times
Right to- (second #) - 3 times
Left to- (third #) - 2 times 
Right to stop (approx. 96)

 The numbers should be at least 10 numbers apart and the last number cannot be between 0 and 20.

2. Dial the existing combination to the changing index (the mark left of center) and stop on the third number.

3. Insert the change key in the hole in the back of the lock and turn 1/4 turn.

If the change key doesn't go in all the way or turn the wheels may not be lined up correctly. Do not force the key. Attempt to dial the numbers to the changing index again .

4. Clear the old combination by turning the dial left 5 times.

5. Dial in the new desired combination to the changing index and stop on the third number.

Be sure to use the changing index for all three numbers with the proper rotations (see above). If you make a mistake clear the combination (5 turns left) and begin setting your new numbers again.

6. Turn the change key back 1/4 turn and pull it out

7. Use the opening index (the center line) to test the new combination 3 times with the door open before locking the door shut.

Be sure your new combination works before attempting to close the safe.


If you have any problems call 780-465-6401 for help.