A trim chain
is used in theatrical rigging
to level the batten
in a counterweight system
. The chain is attached to the wire rope
s that drop from the grid
by a cable clamp. The chain is then wrapped around the batten and bolted to itself. Adjusting which link the chain is bolted to adjusts the height of the batten.
This is necessary because battens often will sag noticeably in the center. In order to support them, the pick points at the center of the batten must be shorter than those at the edges.
Part of the Stage Rigging Metanode