Maurice….interesting reference to your grandfather because the one and only time I have ever seen that tool, (and the reason I know what it is) was in the hands of my own grandfather when he was cutting veneer disks in his workshop during the early/mid 1950's. as near as I can remeber across 60 years the tool was virtually identical to that in your pics. I don't remeber seeing it before or after so assume that he borrowed it for the job. The crossbar and various cutters and pivots were kept in a canvas tool roll. I can clearly remember him showing me how it worked and that he used a flat, leather covered pivot pad held in the square taper to cut out the veneer disks.
…….i forgot about this tool for nearly 60 years but about two years back when I was 'delving' into the methods of 17th C clock makers I suddenly remembered it and came to the conclusion that they must has used a very similar tool to cut out chapter rings and clock faces from sheet brass,…possibly also the actual wheel blanks too. Actually, a tool like this would be quite useful to me now for that purpose.