Definition of "frisket"

And while the Tympan is coming, he slips his Left Hand Fingers from under the Frisket to the hither outer corner of it, as well to keep the Sheet close to the Tympan in its position, as to avoid the jobbing of the lower side of the Frisket against the small square shoulder

1677–1683, Joseph Moxon, “(please specify the page)”, in Mechanick Exercises, or The Doctrine of Handy-Works, […], volumes (please specify |volume=I or II), London: […] Joseph Moxon, published 1678–1683

As the pressman returns the inkballs to the inkstone, the journeyman closes the frisket and tympan.

2000, Richard L. Saunders, Printing in Deseret