The footsticks may be a trifle shorter than the width of two pages and the gutter; for as there should always be a line of quadrats, or a reglet cut to measure, at the foot of each page, the footstick may be a pica shorter without danger, on this account, of any thing falling out, when the form is lifted and it thus prevents the side and foot sticks from binding when locked up.
Source: wiktionary