knocking out the swell
The process of reducing the "swell" in the spine
of a book sewn through the folds by hand or on a
sewing machine. The swell may be caused by the
addition of thread in the folds of the sections.
and also, at times, by the thickness of the paper
used to guard damaged sections. Reducing the swell
is a somewhat delicate operation, as it is
necessary to have additional thickness in the
spine in order to be able to round and back the
book properly; too much swell, however, produces
undesirable results, including a wedge shape, a
greater tendency for the spine of the book to fall
in, and a book that is lacking in firmness and
solidity. Excessive swell may be reduced by
clamping the text block in a lying press, placing
the knocking-down iron against it, and tapping the
side at the spine with a backing hammer, or, as in
the case of library and edition binding, by
smashing or nipping. (339 )
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