C-Clamp (stagecraft)

In stagecraft, a c-clamp can refer to a number of different pieces of hardware, depending on its intended use.

Carpentry

C-clamps are commonly used in theatrical carpentry for the same purpose that non-theatrical carpenters employ them: for creating a quick, temporary, and non-destructive way of joining two objects together. Legs are commonly attached to platforms via c-clamp before they are fastened together using a more permanent method (i.e. bolts). Multi-platform assemblies are also commonly joined to one another solely with c-clamps, especially in touring situations where a set needs to be assembled and struck quickly.

Lighting and Sound

In stage lighting and sound a c-clamp, also referred to as a pipe clamp, is used to attach a larger piece of hardware, such as a lighting instrument, a speaker, or a dimmer, to a pipe or batten. Newer c-clamps tend to be constructed of aluminum, although steel is not uncommon.

C-clamps function by affixing a bolt (the "shaft bolt") to the hardware they are to hold in place, such as through the yoke of a lighting instrument, and securely fastening this bolt to the clamp shaft. The open end of the clamp is then placed over the batten, and a bolt (the "clamp bolt") is tightened to secure the c-clamp. C-clamps for stage lighting fixtures usually also have a pan screw (also known as a "grub bolt"), which when loosened will allow the clamp shaft, and therefor the fixture, to be rotated 360 degrees while maintaining a secure connection to the batten.

When using c-clamps care must be taken to not over-torque the clamp bolt which affixes the clamp to the batten. If this bolt is over-tightened, it can easily dimple or "drill" into the batten seriously compromising the strength of the batten.