Flat bar

A flat bar is a flat strip of metal, rectangular in section, narrow and not very thick.

In metal locksmithing it turns up everywhere. It forms the crossbars that join the bars of a grille, the frame they are fixed into, the reinforcements on a gate and the lugs or tabs that are built into or screwed to the wall to anchor it.

The thickness of the flat bar says a lot about the grille. A thin flat bar bends under a crowbar and leaves the bars loose; a flat bar of sufficient thickness keeps the grille rigid. The bars usually pass through it or are welded to it.

Where the flat bar meets the wall is exactly where salt air shows most: rust swells the metal and cracks the render. If you see it, it is worth treating before the anchoring works loose. We discuss it on our security grilles page.