SPECIFICATION FOR TOOL-PROOF STEEL BARS
1938

1. For the purpose of this specification a tool-resisting bar or plate is defined as one which is not severed within a working period of six hours by using six hand hacksaw blades or pierced by using six 1/8" bits used in hand-operated or motor-driven drill.
   
   
2. The round or hexagonal bars of tool-resisting steel gratings shall be composite bars. One component, (the matrix) shall be iron or steel which does not harden under the treatment which puts the inserts in tool-resiting condition. The other component (the inserts) shall be a tool resisting carbon or alloy steel. The tool-resisting component shall be entirely enclosed in or surrounded by the iron or steel matrix. The composite bar shall be so fabricated that the tool-resisting component and the soft iron or steel matrix are welded, each to the other, throughout the length of the bars.
   
   
3. The tool-resisting inserts, not less than 8 in number, shall be distributed symmetrically about the axis and uniformly throughout the length of the composite bar. The cross-section area of all the inserts shall not be less than 25 per cent of the cross section area of the bars.
   
   
4. Any heat treatment of the bars shall be done in equipment which will maintain the entire bar, or assembly or group of bars, uniformly at suitable temperature. The heat treating equipment shall include instruments that will indicate or record the temperatures of the furnances and of the bars.
   
   
5. All tool-resisting steel plate or flat bars shall be 1/4 inch thick, unless otherwise specified, and shall be composite plate. One component shall be a tool-resisting carbon or alloy steel. The other component shall be an iron or steel which does not harden under the treatment which puts the first component in tool resisting condition. The composite plate shall be composed of five alternate laminations -- three laminations of the soft iron or steel and two laminations of the tool-resisting steel. The laminations of the tool resisting component may be composed of separate inserts of relatively small cross section comprising not less than 25% of the cross section of the plate and so arranged in the finishing plate, that they form in effect two continuous layers of tool-resisting material separating three layers of the soft iron or steel. The composite plate shall be so fabricated that the tool resisting component and the soft-iron or steel component are welded, each to the other, throughout the length of the plate. The tool resisting laminations or inserts shall be distributed symmetrically throughout the cross section and uniformly throughout the length of the plate.
   
   
6. The requirements for heat treating equipment and procedures applicable to plates are the same as those specified for bars.
   
   
7. Each bidder shall submit two 18" lengths of tool-resisting vertical bars and two 18" lengths of the tool-resisting plates of the width of a horizontal bar of the kind and quality he proposes to furnish. The Government shall be accorded the privilege of having a representative inspect the material during fabrication and after installation. Such bars or plates as designated by the inspector shall be subjected to saw and drill tests to determine whether or not they are tool resisting as defined in Paragraph 1.
   
   
8. Each bidder shall submit with his bid the chemical compostions of the steel for the inserts and for the matrix. Manufacturers' mill analyses will be satisfactory.

   TO BE USED AS AN ATTACHMENT TO SPECIFICATION NO. 56, U.S. Penitentiary, Alcatraz, California, dated January 24, 1938.