I have just been sorting my workshop and found my old Arcoy Dovetail machine which I bought 50 odd years ago as a youth, and in the same box was this adaptor made of Aluminium/Steel with an outer ring 4-1/2 inch diameter with an inner ring 3-1/4 diameter which sits inside and both have a recess on the inside of the centre. The inner diameter on the outer ring is 3 inches and the inner diameter on the inner ring is 2 inches.
I have no idea what it is an adaptor for but do not think it is for the Arcoy Dovetailer where I found it.
I know if I throw it away I will subsequently find out what it is for so do not want to do that. It looks like the sort of multiple size Router table adaptor that one normally uses but my router bench has a multi size plastic insert and on checking my old Black and Decker Router has no mention in the handbook or appropriate space to use it.
I am at a loss? Can anyone identify the adaptor ?