This tool, in very bad condition, was found in the same skip as all of the ETA drawings displayed elsewhere on this site by Ian Mander and John A Gibbs. John took the tool away, refurbished it to the excellent condition you see in the photographs and, having found a supply of the correct gasket material, turned a hundred or so out. You can see John's scribings on the end of the tool.

The sprung button on the front of the base of the tool cuts the nick in the outside edge of the gasket. As far as I can see the gasket material enters through the slot in the left hand side of the tool, the first die puches the inner hole and the cylinder head bolt holes, the second die centres the inner hole of the gasket and punches the outer perimeter. The gasket appears on the right of the tool and a button in the path of the gasket raises it for easy separation from the waste.

Perhaps I can persuade John A Gibbs to say if making the gaskets was as easy as I have described it and indeed why the gaskets were only suitable for the ETA 29 6c