Abstract: A metal substrate, and a method of construction thereof, utilizing an elongated mandrel having a drilled hole in a first end thereof, and a torx recess in the second end thereof. A web of metal substrate material is affixed to the mandrel, the web including a first web of substantially planar metal foil and a second web of corrugated metal foil. The torx recess of the mandrel is indexed into operative engagement with a male drive bit of a winding machine, and the male drive bit is rotated to wrap the web of metal substrate material around the mandrel while the web is fed to the mandrel and while maintaining tension on the web, until a metal substrate of desired size is obtained. Utilizing the headless torx recess mandrel, indexing problems in the prior art are eliminated and the mandrel is capable of withstanding the torque of the drive bit turning in one direction and a reverse force created by foil tension in the opposite direction.