Sheet metal parts are kept in alignment by clecos. Clecos are inserted though the holes in sheet metal, and are kept in place by their spring-loaded, expanding metal pins. They are installed and removed by cleco piers.

Clecos come in four sizes. My project uses two: the copper color is for one-eighth inch holes; the black is for five-thirty-second inch holes. Cleco side clamps are also available. They install quickly with cleco pliers and have a very strong holding power.