Coffin Key
Also known as
5/16" Allen Key, 8 mm Allen Key, Hex Key, Truss Key, Spanner Key
Used for
Tightening the couplers (conical connectors) that join truss sections together. The coffin-shaped head provides extra leverage without a ratchet. Every stagehand's pocket should have one.
Trade note
Named for the vaguely coffin-shaped profile of the head. The 5/16" (≈8 mm) hex size is the de facto standard for most European and North American truss coupler bolts, which is why "coffin key" and "truss key" are used interchangeably in touring.
Direct answer
Coffin Key is used for tightening the couplers (conical connectors) that join truss sections together. The coffin-shaped head provides extra leverage without a ratchet. Every stagehand's pocket should have one. It is also known as 5/16" Allen Key, 8 mm Allen Key, Hex Key, Truss Key, Spanner Key. Trade note: Named for the vaguely coffin-shaped profile of the head. The 5/16" (≈8 mm) hex size is the de facto standard for most European and North American truss coupler bolts, which is why "coffin key" and "truss key" are used interchangeably in touring.
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