The original assembly used rivets along the cone's longitudinal seam and around its connection to the raised sub-base flange. We replaced the rivets at both locations with pressed, interlocking sheet-metal folds. The support brackets kept their original connections.
Both revised joints use folded sheet edges that interlock under pressure.
Riveting the rolled cone required hole preparation and individual fastener placement, leaving a row of exposed heads along the seam.
We formed mating returns along the sheet edges, nested them together and pressed the folds closed. The resulting mechanical lock joins the cone without separate rivets or rivet holes along the seam.
The sub-base is pressed from galvanized steel sheet, with a short flange raised around its central opening. Rivets originally fastened this flange to the cone's lower edge around the perimeter.
We folded the cone's lower edge and the raised flange into mating returns, then pressed them closed around the rim. The same interlocking principle eliminates the rivets from this connection. The upper assembly uses weather-resistant pre-coated steel sheet.
Removing rivet placement and setting from both joints reduced assembly work and removed the exposed rivet heads. The revised vent also has a cleaner finish along the cone seam and lower perimeter.
Lower purchase price per complete vent unit compared with the original configuration in this project.