DANDY ROLLS 231
When using a roll with letters or designs on a thin paper it will be found
that the raised letters, etc., pick up fibres or bits of pulp, the size of which
increases with each revolution, until they fall or are brushed off by the machine-
man. These are termed 'dandy picks' or epicks' and are responsible for a great
percentage of broke in thin papers. A small diameter roll, or one with heavy
designs, gives most trouble. The remedy is to raise the roll carefully, so as
to take as much weight off the stuff as possible without losing the clearness of
the water-mark, or to reduce the speed of the machine, or to increase the length
of the fibres, by altering the beating.
Therefore the character of the water-mark and the suitability of the roll
have to be considered when trying to increase speed on a thin paper. An
increase of speed is of no value if die proportion of broke from this cause is
also increased.
A strip of old wet felt, called the 'wiper*, is suspended by a rod over the
dandy roll, and may be let down on it when running at a low speed. It is
an excellent device for keeping the roll clean and free from 'picks', if it can
be used. Wove rolls are liable to fill up with froth, when they have to be
taken off the machine and washed out. Fine sprays of cold water are sometimes
used on the roll to prevent the froth forming. A rubber roller running on
top of the dandy will be found of great use in collecting the bits of stuff picked
up by the dandy. This roller throws them on to a cloth fixed in front of the
dandy.
Dandy rolls with designs that must register correctly have to be set in correct
parallel across the machine to bring the designs square with the cut sheet.
The draws or tensions between sections of the machine are used to bring the
water-mark correct with the cutting length or 'chop'. Often a roll will be
found to be short in the draw, and after all the sections have been pulled tight
the draw is still too short. A few turns of tape, or one turn of-thin old wet
felt round the ends of the daady roll outside the deckle edge of the paper, will
lengthen the distance between the designs, and it is more prudent to do this
than pull up d>e sectioi& too hard. If the wiper can be used, it will give a
fraction of an inch more length by slightly dragging the roll. The register of
the water-marks across the roll is more difficult to alter. On narrow deckles
(up to 60 inches) they are seldom far out, but on wider sheets, such as four or
five sheets of i6i inches, the beating and quality of the fibres may alter the
shrinkage by as much as 2 inches, The beating of the stuff must then be altered
to bring the width into register with the roll. If the draws can be altered the
width may be controlled a little, so that by putting a turn or two of tape
on the roll the length may be brought out and the draws put back, which will
give more space between names across the roll.