Two joints of the simplest construction, by which the frisket is attached to the tympan by means of two pins, made with a head to each, so that they can easily be taken out with the fingers; they are inserted between the joints, and thus the heads face each other.
It is customary to place these joints on the flat part of the headband of the tympan, which, when a large form is on the press, and the rim of the chase is broad, rest upon, and prevent the form receiving the effect of the pull. I have known great inconvenience arise from this cause, in very superior work, where the chase filled the press, and could not be moved to get rid of this grievance. The joints should be taken off, and fixed to the extreme edge of the headband, by which means they will extend beyond the chase, and the evil be completely remedied. Where the frisket is fixed on centres this inconvenience does not exist.