BREAST BOX	161
oscillating board. This may be accomplished by having the breast box* at a
sufficiently high level to allow the stuff to pour over the lip into the recess of
the breast board. Another way is to bridge the gap with a strip of some strong
flexible material which is fixed to both the stationary and the moving board
by a continuous strip of metal and counter-sunk screws.
The material called 'moleskin' used to be very popular for the purpose,
but its hairy surface makes 'drags' in strong papers. Thin and flexible
leather may be obtained for the purpose, and if carefully fixed and used will
be found to give good service for about twelve months before having to be
renewed. In an emergency, a strip of good old rubber apron will answer the
purpose.
The connecting strip should be examined for any cracks or holes when the
machine is shut—about once a week, otherwise a loss of stuff may occur and
remain undetected for a long time. It should be kept wet over the week-end.
From the breast board the apron receives the stuff and delivers it to the
wire. The apron should conform with the following requirements: It must
be thin, tough, smooth, non-elastic, composed of a material that will not rub
off in pieces or flakes, or wear to a frayed surface, or edge, or wrinkle up with
changes of temperature or humidity. Fibrous materials, varnished or water-
proofed, are sometimes used, but these cause trouble, since threads at the extreme
edge where the material is worn by the wire make streaks and lumps, especially
in tinted papers and blues and azures. Even one cotton fibre streaming from
the edge, and so small as to be almost invisible, will do this.
The life of the apron depends in a great measure on whether there are
many changes of deckle and the care which is taken by the machinemen in
making these changes; also on the method of making a reasonably water-tight
joint at the first deckle pulley. The best method is the roller apron. The
apron is taken underneath a brass pkte just inside the pulley and rolled up on
a small cylinder which is kept at tension by a cord and weight. This plate is
made to be adjusted as close as possible to the wire, leaving just enough space
to let the wire run without nipping the apron. The latter is fixed to the breast
board by a brass strip and countersunk screws, except for that length at both
sides of the machine that is allowed for the maximum and minimum breadth
of deckle. A slip of brass, bent to a knee shape, keeps the loose part down
on the breast board, and may be pressed down to make a water-tight joint.
When drawing out the deckle, the roll on the cylinder must be eased off to
let the apron pay out freely and the plate and brass slip put carefully down
after the dhange is mack.
When putting the cleekk into a narrower width of sheet, the plate and slip
should be raised tij> aacf the cylinder helped to roll up the loose apron. Tjlie