Welcome to our world exploring the Historical, Political and Technological aspects of Locks, Keys and Safes

Results 1 to 6 of 6
  1. #1
    Join Date
    Nov 2014
    Location
    Bulgaria
    Posts
    686
    Country: Bulgaria

    Default Chatwood duplextra

    In another thread I mentioned a Chatwood Duplex which was classed as a sub standard plate safe because it was just a 1/4 plate shell although the front was of standard duplex quality. This was because it had originally been designed as a night safe and was concreted into a wall. It was not designed to take cash, but that is another story.

    COD got their hands on it and under my instruction altered it more than a little. They riveted progressive layers of various metals inside the skin including IT100 armour plate, copper and stainless. They then fabricated a box inside and poured high aggregate concrete, reinforced with expanded metal and vibrated that until it formed a monolith between the skins. This was all poured in through the base, I think.

    As a night safe the casting at the bottom of the frame was deeper than the top and sides by a couple of inches but the monlith was uniform thickness all round. That left an area the size of the whole inside and a couple of inches deep in the base. When making the body they had incorporated base fixing holes. These were covered by a sliding panel at the level of the base of the door. I had to remove 4 allen bolts which fixed it in place and just slide it out like the lid of a pencil case.

    I think most readers will be aware of the basic weakness of a duplex. They altered things to remove that weakness but I am not about to describe the weakness on a public forum.

    They also extended the boltwork and added a very neat live AED immediately above the lock. Of course we kept the standard dead AED, with the hole in the boltwork offset so as to frustrate a preloaded handle attackThe most amazing thing was that they machined 2 keys out of solid steel. These were double bitted and that dual control lock is to some fairly tight tolerances! I don't know how long that all took but the keys were superb!

    In case anybody reading this has never seen the dual control lock, I shall explain. It looks on the outside just like any keyway for a Chatwood double bitted key. There is only 1 keyway. To open, key A is inserted and tuned through 180 degrees and removed. Then key B is inserted through 90 degrees at which point it stops. To lock the unit key B is turned back 90 degrees and removed. The safe is then completely locked and you need bot A and B to reopen it. How neat is that?

  2. #2
    Join Date
    Aug 2013
    Posts
    1,754
    Country: Wales

    Default

    Good to see you've got your memory back chubby, was getting worried when you started the "John Tann Isolator Boltwork" thread.

  3. #3
    Join Date
    Oct 2010
    Location
    leeds
    Posts
    609
    Country: Great Britain

    Default

    I remember having to kango out the inner and outer nightsafe units, we normally did them over the weekend and you earned your money!
    Love dual control locks and have a few of them in my collection, the one you are talking about , was it the impregnable? I seem to remember one where some levers were slightly longer than others and key 1 just moved the bolt a little way into the longer lever gates, followed by key 2 that took the bolt the rest of the way.

  4. #4
    Join Date
    Nov 2014
    Location
    Bulgaria
    Posts
    686
    Country: Bulgaria

    Default

    I see how that would work, but how does key B relock the lock fully?

  5. #5
    Join Date
    Oct 2010
    Location
    leeds
    Posts
    609
    Country: Great Britain

    Default

    If I remember correctly there is a little spring loaded catch on the bolt talon that will only spring one way allowing
    the bolt step of a key to pass one way,but catching and engaging when turning the other way, so the key will throw different distances depending on rotational direction.

  6. #6
    Join Date
    Nov 2014
    Location
    Bulgaria
    Posts
    686
    Country: Bulgaria

    Default

    It is all very clever.

    Chatwood used to make an excellent machine. I think this was the trouble with a lot of those old companies. They would build an excellent safe, and it would last several lifetimes. That is not good for business.

    My brother recently got locked out of an electronic safe at work. He hit it smartly on the top, which jogged the servo, and turned the handle at the same time and got it open.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •