stuffing nut

English Thesaurus

1. a nut used to tighten a stuffing box (noun.artifact)

hypernym	:	nut,
definition	:	a small (usually square or hexagonal) metal block with internal screw thread to be fitted onto a bolt (noun.artifact)

part meronym	:	packing box, stuffing box,
definition	:	a small chamber in which packing is compressed around a reciprocating shaft or piston to form a seal (noun.artifact)