The Foden High and Low pressure valve covers were supplied as a one piece casting, so needed to be cut. There is very little room for error as the casting are already cast dimensionally under size. So a minimum clean up around the edge, could only be achieved. The castings were already 1/32" undersize before clean up, so minimum amount removed with cast witness marks left around edge. The castings should also be 3/16" thick but if this had been achieved the details would be lost on the casting. so opted to make 1/4" thick.
