Flush Bolts

Choosing Flush Bolts for Paired Doors

Flush bolts are commonly used on the inactive leaf of paired doors so that leaf can be secured at the head, sill, or both while the active leaf operates normally. Manual flush bolts are operated directly by the user, while automatic and constant-latching systems interact with the opening or closing sequence of the door pair. The correct type depends on the door assembly and how the inactive leaf must operate.

Door construction is a key compatibility point. Flush-bolt bodies and mounting preparations can differ for wood and hollow-metal doors, and top and bottom bolts may use different rods, guides, strikes, or body dimensions. Measure the existing preparation and identify the current hardware series whenever possible before ordering a replacement component.

For manual bolts, compare body size, faceplate dimensions, bolt throw, rod or extension length, operating lever, and strike configuration. Automatic or constant-latching bolts require additional attention to the coordinator, active-door relationship, trigger or release mechanism, top and bottom latching arrangement, and any manufacturer-specific accessories needed for the complete system.

Paired fire doors and other regulated openings can have specific requirements for latching, sequencing, strikes, coordinators, and listed components. A replacement bolt should preserve the required operation and listing of the complete assembly. Confirm the manufacturer's compatibility and installation information for the door type and use qualified commercial door-hardware professionals when the opening has fire, egress, accessibility, or other life-safety requirements.

Finish matters mainly on the visible faceplates and trim after the mechanical requirements are established. For replacement work, matching the preparation, rod length, strike, bolt function, and device family is more important than matching finish alone. Review what is included with the individual product so paired bolts, top-only components, rods, strikes, and accessories are not confused with complete sets.