During the fixing, the opening and shutting of the door should be tried frequently. As cement swells in setting, it is possible a door-frame which appears to be properly set may afterwards be found bulged or bound when dry. This should, therefore, be guarded against by wood struts placed across the inside of the frame. On no account must a frame be fixed without its door, but always with the door hung and open, in accordance with the foregoing directions.
As the keys are not required by the workmen after the door is unlocked before fixing, they should be kept by the owner, lest by being left about they may be mislaid or wrongfully used.
A strong-room door of ordinary quality should have the outer plate ½ or ⅝ inch thick, with the lock-case and fireproofing-case in addition; and at least six bolts, three at front and three at back; the frame of a strength proportionate to the size and weight of the door, and with arms and lugs projecting, to build into the wall.
The interior fittings of the room are of course determined by the requirements of the owner. If there is much shelving it may be of perforated metal or mere strips of iron for boxes to rest on, so as to allow of free circulation of air. For particularly valuable articles or documents a safe either small or to take to pieces may be introduced, as is usually done by bankers. I give a plan of a first-class strong-room, which for all practical purposes is secure, and combines strength with economy in construction.
