by aacmajor » 16 Mar 2007 19:44
I had the oppurtunity to shim a bunch of locks off high school lockers so they could be replaced with "key accessible" combination locks. Some were Master, some were Slaymaker, and some were an unknown Chinese type. The method that I use in my shop has worked with all types. Even with the Master locks, it reduces the number of combinations from 64 to about 10- 15.
First, clear the lock by turning the dial three times to the left. Then take a jewelers screwdriver and wedge the striker/ latch back so that you have a better view inside. Then turn the dial right three times until the gate on the first disc (closer to the rear) comes into view. Record the number on the dial. Then turn the dial twice to the left until the gate from the middle dial comes into view and lines up with the first dial (this can be done fairly easy by lining up the corner of the gate.) Record the number on the disc. Finally, turn the dial once to the right until the gate on the third disc (closest to the dial) comes into view. Line it up with the other two gates and record the number.
These three numbers are not the combination but rather the span needed to align the gates. Subtract ten from the numbers and pull the shackle. If it does not move, SUBTRACT one from the numbers and try again. Continue this until the shackle opens. If the shackle does not open after ten tries, return to your original number, subtract ten from each number, then ADD one as you try the shackle.
Example: You line up the gates and get the numbers 19-39-19. Subtract ten and you now have 9-29-9. Try this number. If it does not work, try 8-28-8, 7-27-7, 6-26-6, etc, until you have tried ten combinations. If one of those did not open the shackle, go back to 9-29-9 and work your way up: 10-30-10, 11-31-11, etc.
We have always been able to determine the combination on dial locks using this method. I hope I explained it in enough detail.
DJ Barron