Hello Tom,
Chubb seemed to have changed their design for the turning near to the bow on PIN keys, from three plain bands to a more fancy design when they moved to 128 Queen Victoria Street in about 1877. The attached photos agree with this rule of thumb with one exception, which must have been made around 1877. However, they retained the three plain bands for their PIPE keys well into the twentieth century. I wonder why the turning style, after 1877, was determined by whether it was for a pin or a pipe key?
Karl.


