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Hi Andy, I have been working on a Mosler Round Door Safe in my garage and I was wondering if you could answer a few questions that I have about it. I am about 99% sure it is a 4 wheel lock and it looks slightly different than the (Mosler 302 dial with the black center) and instead of the knob getting smaller the closer it gets to the dial, it gets larger and is tapered the opposite way than the 302. See Pics. The dial ring has a changing index on it. Question # 1. Can you tell me of what style of lock this is? #2. Is the dialing direction Right-Left-Right-Left? Question # 3. Is the opening inside the safe extremely small like 1 cubic foot? At first I thought the walls were about 3 inches thick but when we set it on my trailer it seems to weigh about 1200 lbs. estimate. Thanks for what ever info you can give me.

Hi Dave,

Generally this type of Mosler Lug Door, with the tapered Mosler dial, with the gold checkered center, usually has the Mosler RB-104.   This should be a four wheel lock, with the dialing sequence of RLRLR.    This type safe with this dial MAY also have the Mosler KCB-101, this is also a four wheel lock but it dials LRLRL.   The RB-104 is much more prevalent, so without further info, I would probably assume that this would be the lock mounted on this door.   Basic dialing diagnostics would confirm which lock you actually have.

The dialing sequence should be:

5 times Right to the first number,
4 times Left to the second number,
3 times Right to the third number,
2 times Left to the fourth number,
1 time Right until the dial stops, around 88

Lastly, the interior is going to be around the same size as the "square" area the door is recessed into.    About 1 foot square, and possibly 16" to 18" deep.   Maybe slightly less.

Note:   The RB-104 is a hand change lock while the KCB-101 is a key change lock.   The presence of the changing index doesn't necessarily indicate the presence of one lock or the other.  The best indication would be checking the drive wheel contact points.   A narrow contact area would generally indicate the RB-104.

Hope this helps,   While it still leaves you with some options, it did narrow it down to TWO locks.  


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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

Past/Present Clients
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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