Locksmithing/Diplomat MC-350


I recently acquired a Diplomat MC-350, and the previous owner left me the combination and key, but I can't get it to open. You posted some helpful info on this safe on 4/11, but I'm having trouble understanding it.


You said "The first (1st) number must pass the index mark three (3) times in a clockwise (right) direction and stop on the fourth (4th) full turn." So, if the number was 20, I rotate clock-wise 3x past the zero and stop on the '20', or rotate 4x past the zero and stop on the 20? If you were to give an example, it would really help.

Also, the combo he left says to start rotating *counter clock-wise* for the first number and alternate from there. Does this make sense from your experience with Diplomat safes?  Thanks so much for your help!


Don't worry about or concentrate on "passing" the index  mark, and/or the revolutions of the dial.   Generally this is where most people "screw up" at.    ONLY count the individual number, that you are currently working with, each time that it ARRVIES at the index mark.   Also forget zero (0 or 100).  Trying to "work" zero (0) into the dialing sequence will ensure that you don't get the safe open!!!   If it is NOT part of your combination, then it is NOT part of the dialing sequence.
For instance if you have the following dialing sequence:

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 (or to your last number).

Left is counter clockwise and Right is clockwise.   so if your first number is "20", simply start dialing counter clockwise (left), stopping the FOURTH time the number 20 arrives at the index.   Or, dialing left to 20 once, 20 twice, 20 three times, stopping on 20 the fourth time it arrives.
You are now finished with this number - FORGET IT, it no longer matters - concentrate on the next number of your combination.
If it is 85, you will now turn the dial clockwise (right), stopping the third time the number 85 arrives at the index mark, or right to 85 once, 85 twice and stopping on it the third time.

Sorry but this is really a simple concept once you quit trying to count revolutions or passing "0" or any of the other nonsense, and will work on EVERY combination lock on the plant, with only adjustments L or R, depending on the manufacturer of the lock and the number of wheels present.

There are ONLY three reasons that a safe lock will not open.   The NUMBER ONE reason is:
1.  Incorrect dialing sequence - OPERATOR ERRORS!!!
2.  Incorrect combination - wrong numbers,
3.  mechanical problems.

If this still doesn't work for you, then I would recommend stopping at a local safe company to have them actually show you on a working safe.   Take your combination with you so that they can dial your numbers and give you the idea.

I hope this helps explain the dialing sequence a little better, and quit adding stuff in, which only serves to confuse you.   Keep it simple.


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Terry V. Andreasen (Andy)


Safe and Vault related Questions; Antique Safe Repair and Restoration; With over 40 years in the Safe & Vault industry, if I can't answer your question I know where to get the answer. Current Project: Restoration of two Tilton & McFarland safes from the 1860'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.


40 years in the Safe & Vault Industry. 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

SafeCrackers International and the National Antique Safe Association

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.

Awards and Honors
2009 - 2014 - 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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