Wall Box - Construction

Construction

Wall boxes are normally made of cast iron and are fabricated in two large castings with a third casting for the door. The rear part of the box which is set into the wall is cast as one piece, rather like an upright coffin. The whole front of the box including the aperture, royal cipher and the collection plate holder, are cast as one. There is a large opening in the front casting into which a hinged door is inserted. It is held in place by steel pins at top and bottom which locate into machined holes in the front casting. A secure 5-lever Chubb lock is fitted to all wall boxes made after 1870. Previously, narrower locks from the firm of Nettlefields were used. They are not interchangeable and this causes problems when keys are lost and locks have to be changed.

Initial examples were fitted with a simple wire tray internally over the base to raise any post off the lower surface. This was necessary because water seeped into the box through the side seams and condensation could also form on the inside, making the base rather wet. Later modifications saw this wirework extended to form a vertical barrier across the whole inside front of the box. This prevented mail from cascading out onto the ground when the door was opened for clearing the box. By 1879, UK wall boxes were also fitted with a drop-down hinged metal letter chute to help guide the stored mail into the waiting sack or basket during clearance.

An even later modification, which was then widely retro-fitted, was the provision externally of a Next Collection tablet holder to hold the square metal tablet inscribed, enamelled or printed with the time or day on which the next collection is due to be made. At the same time, internally, a tablet storage box was added to hold the remaining day or hour tablets not currently in use.