clapper box

clapper box

[′klap·ər ‚bäks]
(mechanical engineering)
A hinged device that permits a reciprocating cutting tool (as in a planer or shaper) to clear the work on the return stroke.
References in periodicals archive ?
Clapper Box: The clapper box is needed because the cutter drags over the work on the return stroke.
They also have a clapper box (often with power lift) like the shaper.