How Does an Interlocking Bronze Door Threshold Work?

An interlocking bronze door threshold uses two matching metal profiles: a threshold at the sill and a J-hook attached to the bottom of the door.

When the door closes, the J-hook engages the interlocking part of the threshold. The seal is created by the two metal profiles meeting correctly.

Because the hook and threshold have to line up, the installation depends on fitting the threshold first and then preparing the door bottom to match it.

See the complete photo sequence in How to Install an Interlocking Bronze Threshold on a Door. If you are working with an existing system, see What is the J-hook on an interlocking bronze threshold?