History of Locks
Kromer ’ s Krosimplex Safe Dial
Another insightful article in our revisited History & Heritage series from Brian Morland , Curator of The History of Locks Museum . This time , Brian tells us about another treasure from the Museum ’ s extraordinary collection - Kromer ’ s Krosimplex Safe Dial .
A LOT TO THINK ABOUT …
Dialling a traditional three or four wheel combination lock requires a certain amount of mental dexterity . There is a lot to think about , the combination numbers , the start direction , accuracy of dialling , number of rotations for each number , changing direction , and all this ideally held in memory . Add to this any day-today preoccupations that the user might have then you have a recipe for a high number of frustratingly failed dialling attempts .
The normal procedure for dialling a four wheel combination lock might be : -
• Turn the dial five times in a clockwise direction carefully stopping at the first combination number .
• Turn the dial four times in an anticlockwise direction carefully stopping at the second combination number .
• Turn the dial three times in a clockwise direction carefully stopping at the third combination number .
• Turn the dial two times in an anticlockwise direction carefully stopping at the fourth combination number .
• Turn the dial clockwise to open .
^ One of Bill Stanton ’ s practice lock , from around the late 1940 ’ s , with which he learned the necessary techniques including trouble shooting .
You can see that the sequence requires concentration particularly to aligning numbers when changing direction , as any over or under dialling requires the whole sequence to be started again .
The locksmith has an advantage over the banker , commercial user or private user in that he knows intimately what is going on in the lock and the reason for
^ Bill Stanton pictured here in the mid 1960s when he was working on Kromer projects including what was to become known as the Krosimplex dial .
counting rotations and changing direction and , therefore , these details are intuitive to him whereas to the customer user they are just an annoyance .
One common problem , sometimes encountered by users when dialling a combination , was mentally counting the number of rotations for a particular number before changing direction for
A contemporary artists sketch of the dial from Kromers own booklet .
60
MAR / APR 2023
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