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Locksmithing/Unknown safe with Mosler combination lock


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QUESTION: Good day Andy
I am approaching you from the other side of the big pond as nobody in my vicinity seems to be in a position to help me with the following issue:
The safe in question had been used by my father for many years until they moved out of their house and I moved in with my family. One of the changes I did to the interior was to change the combination of the lock in question. I have not touched the safe for a long time but wanted to get access recently and found that the combination I had in mind would not work. I tried all permutations of my favorite numbers for such cases but to no success. After several hours of trying I approached a well reputed safe manufacturer here in Switzerland who offered to open it by drilling but the lock would be gone. Reading through the vast material available in the net told me that it should be possible to get this opened without destroying the whole.
May I ask you for advice on how to proceed and maybe you would know a company here that would be able to open this without destroying everything.
Thanks a lot for help and best regards from Switzerland

ANSWER: Konrad,

while I would be more than happy to fly to Switzerland to work on your safe, it would be kind of expensive.   I always warn owners to be wary of ANY locksmith or safe technician who would indicate that they can do certain work but will destroy or ruin a lock in the process!!!
This would be like taking your car in for an oil change and having the mechanic indicate they will ruin the motor in the process.   Well, maybe not quite, but I like the analogy!  LOL.

If your local safe technicians don't have the skills or knowledge to manipulate the lock open, it may have to be drilled.   Drilling by a trained professional safe tech should only utilize a very small hole, possibly less than 1/4" (7mm or less), into a void in the lock, and using a fiberoptic scope, decode the lock to open it.  I routinely drill safes like this with about a 1/8" hole to open them, but I have the equipment to utilize this small hole, your local techs may not.
Correctly done this should NOT damage the lock, dial or dial ring, and the hole should easily be repaired.

Unfortunately I don't have any contacts there either.

---------- FOLLOW-UP ----------

QUESTION: Good Day Andy
Thanks for swift reply. You would be welcome as my guest in turn for opening the safe ;-)
Would you be able to tell what sort of Mosler lock this might be? Have not found any hints in the web when entering Chest CH-76
The lock consists of 3 brass discs and I was told that the sequence was right to first, left to 3rd time the second, left to 2nd time the third and then right till it opens. Usually they seem to be different in the direction and starting with left to the first number...
How many turns should the last move take until it opens?
Merry Christmas to you (in case you are celebrating)!

ANSWER: Konrad,

The markings on the front of the safe probably have nothing to do with the actual safe.  They are probably references to ownership by the original purchasing company.

The CH-76 may be the safe number or number of units in inventory,
Serial number may or may not actually be the safes serial number (doesn't match Mosler serial numbers)
Order number, may reference the original purchase order it was bought under.

Unless you have access to information from the original owner, this info is useless.

Where did you get the information about the lock having three wheels???   The lock that I would expect to see on this safe, would be a Mosler B-6 lock.   This was a 4 wheel lock with the following dialing sequence:

5 times left to the first number,
4 times right to the second number,
3 times left to the third number,
2 times right to the fourth number,
1 time left until the dial stops (may be around 10).

If your lock does only have 3 wheels, then the lock would either dial as:

4 times left to the first number,
3 times right to the second number,
2 times left to the third number,
1 time right until the dial stops (around 80).

If this doesn't work, try reversing the directions or RLRL vs RLRL.

NOTE:  Left is counter clockwise, Right is clockwise.  DO NOT count the revolutions of the dial, count the INDIVIDUAL number as it arrives at the index mark.  For example if your first number is 50, in the first example above, you would turn counter clockwise (left), stopping the fifth time the number 50 arrives at the 12 o'clock index mark - or left to 50 once, 50 twice, 50 three times, 50 four times, stopping on 50 the fifth time it arrives.

If the dial does not come to a complete stop during its revolution, then either you have made a dialing error with your combination, or it simply was not the correct numbers.

Hope this helps,

---------- FOLLOW-UP ----------

QUESTION: Thanks for this, Andy
As mentioned in my first question, I have changed the code myself and since then have not been able to reopen it.
I was too silly not to test it several times before locking...
So there are 3 brass discs and there is no key needed to change the code. I just moved the markers to the new combination as I figured that this would do the trick.
Does this give any further hints to the type of lock?
What is the problem if I selected some number close to 0?
Thanks for your time!


Oops! you did mention that originally.   Mosler used a number of different types of locks some of which were hand change, some pin change and some key change.  I'm not sure by "marker" if you mean inserting the pin into a new hole, if so this would be a pin change type lock, possibly a Mosler B103.   The B101 had brass "mesh" type wheels, similar to a car tire.  with the wheel on the outside and a hub on the inside.  Pulling down on the wheel and pressing up on the hub would separate the two, then rotate the hub to a new position, aligning its index mark with the new number on the wheel and pressing them back together.
The B103 series allowed you to reposition a washer/pin assembly to a new hole in the wheel, which gave the wheel a new assigned number.

The dialing sequence for this lock would be:

4 times Right to the first number,
3 times Left to the second number,
2 times Right to the third number,
1 time left until the dial stops (around 10-20)

Please note that regardless of the lock in use, the previous dialing sequences and this one, follow the same general pattern.   If dialing the LRLR sequence does not work, then try the RLRL sequence.  If neither work, then the numbers that you are using are probably NOT correct.

There are two problems associated with selecting the third number near the area where the lever assembly interacts with the drive wheel.  We refer to this as the "forbidden zone", meaning that you don't select the third number in this area, which would be a minimum of 10 numbers on either side of the point where the lever engages the drive wheel.
If the drive wheel engages at 0 (or 100), the forbidden zone would be from 90-10, if the drive wheel engages at 10 the forbidden zone would be from 0-20.

Problem one - as the drive wheel comes from the third number towards the drop in area, (depending on the third number), the drive wheel may try to move the third wheel as it enters this area, moving it out of alignment with the other wheels.
Problem two - the lock unlocks correctly, but as the drive wheel is move back towards extending the locking bolt, and lifting the lever back to the locked position, the third wheel is also moved by the drive wheel, effectively capturing the lever.   We term this as being "locked in".  The lock has to be disassembled and manually moved to the locked position.  Generally in this case, opening the safe is not the problem.

Problem two is usually the result of positioning the chosen number for the number 3 wheel in the forbidden zone, though problem one is generally associated with positioning the chosen number for the third wheel on the lower side of the drop in position.

Another problem that you may have, is writing down the numbers you assigned, associated with the wrong wheels.
On a hand change wheel pack, the number at the bottom of the stack is the number one wheel and first number of your combination.   if you wrote this down as the third number, your combination may be written down back wards.
Also depending on the way the wheels have the numbers written, it is easy to pick a number on the wrong side of the stamped numbers.   For instance if you aligned two tick marks on one side of the number 60, did you actually pick 62 or 58???   This is a common mistake that we see made on hand change type locks.

So thinking about the possible "SIMPLE" mistakes that could have been made, will give you several more combinations to try.  You only have TWO dialing sequences, but you have up to 1,000,000 possible combinations to try.

Hope this helps somewhat.  


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Terry V. Andreasen (Andy)


Safe and Vault related Questions; Antique Safe Repair and Restoration; With over 42 years in the Safe & Vault industry, if I can't answer your question I know where to get the answer. Current Project: Restoration of an Ely Norris Cannonball Safe from the early 1900's. Will answer Safe & Vault related questions concerning age, value, restoration, moving, opening & repairing, parts, operation and history. Note: It is not my intention to teach you to open safes or to provide information which may aid in the unlawful opening of a safe. I will not give out drill points or information which I deem inappropriate.


44 years in the Safe & Vault Industry. Owner and Service Manager for one of the largest Safe & Vault companies on the West Coast. Graduate of Lockmasters Safe Lock Servicing, Safe lock Manipulation and Safe Deposit Lock Courses. Graduate of Locksmith Institute. Certified Instructor for the California Locksmith Association teaching Basic and Advanced Lock Servicing, Basic Safe opening and Repairing. Factory Trained by AMSEC, LORD Safes, LeFebure, Mosler, KabaMas, LaGard and Sargent & Greenleaf Author of "The Coffee Table Guide to Antique Safes".

SafeCrackers International and the National Antique Safe Association Safe & Vault Technicians Association (SAVTA)

The Coffee Table Guide to Antique Safes

Graduate of Locksmith Institute 1972 Graduate Lockmasters Safe Lock Servicing 1974 Graduate Lockmasters Safe Lock Manipulation 1975 Graduate Lockmasters Safe Deposit Lock Servicing 1985 Instructor Certified - California Locksmith Association - 1985 Factory trained by AMSEC, MAJOR, STAR, Johnson-Pacific, Kaba-MAS, Allied-Gary, ISM, Lord, Brown Safe, EXL, Mosler, Diebold.

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2009 - 2015 - Listed in AllExperts Top 50 Experts. All Expert Categories - Safes & Security Containers, Locksmithing, Antique Safes. Retired US Army Chief Warrant Officer (CW4), with 39 years of total service. With numerous awards from Vietnam, Desert Storm and Operation Iraqi Freedom. US Navy - 1971-1981 US Army Reserve 1984-2013 US Army Retired

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US Secret Service, FBI, BATF, Local Law enforcment agencies, Diebold, Hamilton Pacific, Red Hawk Int., Chubb International, Bank of America, Wells Fargo Bank, Mechanics Bank, El Dorado Savings Bank, many Credit unions and smaller banks. McDonalds, Togos, BurgerKing, TacoBell, Carls Jr. FoodMaxx, SaveMart, Lucky's, Albertson's, Raley's, Safeway, NobHill, Bell Markets, PW Markets. Great America, Century Theatres, Cinemark Theatres, UA Cinemas, and many homeowners and small businesses. Provide warranty service for lock and safe manufactures. Service Area is Northern California (Fresno to Oregon and Western Nevada)

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