Due to popular demand, Sonex Flanging Dies are back in-stock! These simple tools are used to form lightening hole flanges in sheet metal ribs and formers. Available in 3 inch and 4 inch diameter, Sonex flanging dies are made from durable fiberglass reinforced injection molded plastic. They are tough-enough to use with a hammer or a press. Sonex Flanging Dies can be used on any project requiring 3 inch or 4 inch flanges in aluminum sheet, including Sonex A-Model and Sonerai scratch-build projects. Sonex Builders can also purchase Flanging Dies as-part of the Sonex Form Block Kit.