Chief CMS391

The Chief CMS391 is a dual joist ceiling mount adapter designed to provide a solid, discreet base for ceiling-suspended projector installations. Engineered for 61 cm (24") on-centre joist spans, it gives AV integrators maximum placement flexibility without requiring structural modifications. The plate attaches directly to finished ceiling joists using included lag bolts, or to structural concrete ceilings using anchors. Its 1.5" NPT threaded fitting accepts standard Chief extension columns, making it the starting point for a wide range of projector mount configurations. Aluminium construction keeps the unit lightweight while maintaining a load rating well suited to heavy commercial projectors.

Flexible 61 cm Joist Compatibility

The CMS391 is sized specifically for 61 cm (24") on-centre ceiling joists — the most common structural spacing in commercial and educational buildings. This removes the need for a custom backing plate or additional blocking, saving significant installation time. The adapter sits unseen above the finished ceiling line, keeping the installation clean and professional. A built-in lateral shift mechanism allows fine-tuning of the projector's horizontal position without repositioning the entire plate, which is invaluable when aligning a lens to a fixed screen.

Integrated Cable Management

Cables exit through a dedicated port at the top of the plate rather than dangling alongside the column. This keeps power and signal cables routed inside the mounting assembly from the very first connection point, resulting in a tidier installation that is easier to service. In environments where ceiling aesthetics matter — such as boardrooms, lecture theatres or premium retail spaces — concealed cabling from the plate upward means no exposed wiring is visible even when the tile or ceiling panel is temporarily removed for maintenance.

One plate. Two joist spacings. Zero compromise on security.

Aluminium construction · 226,8 kg rated · 10-year Chief warranty

All-Points Security System

Chief's proprietary All-Points Security System uses exclusive locking hardware at the column connection point to prevent the extension column — and therefore the projector — from being removed without authorisation. For installations in semi-public spaces such as classrooms, conference centres or hospitality venues, this is a meaningful safeguard against accidental dislodgement and opportunistic theft. It also provides an auditable connection that an installer can verify during commissioning rather than relying solely on torque feel.

High Load Capacity in Aluminium Construction

Despite its lightweight aluminium build, the CMS391 is rated for up to 226,8 kg — far beyond even the largest commercial projectors. The aluminium profile keeps the hardware itself light (shipping weight approx. 2,8 kg), which simplifies one-person overhead installation and reduces structural load on the joists. The generous safety margin means the same plate can be specified across a site without calculating load case by case, and gives system designers confidence when the installation includes heavy lens-shift projectors or additional rigging accessories.

Broad Installation Versatility

Beyond standard joist ceilings, the CMS391 can be installed on solid structural ceilings using concrete anchors (not included), meaning the same SKU covers both timber-frame and concrete construction. It is also compatible with any 1.5" NPT extension column, which includes Chief's full Speed-Connect adjustable column range. This compatibility with an existing ecosystem of columns and projector mounts allows installers to specify the CMS391 as a standard base component across diverse projects, reducing the number of different adapter SKUs needed in stock.