This press can forge ingots up to 45 inches in diameter. The ingot under the press is shown in a partly forged state. Note that the original octagonal shape of the ingot as it came from the mold has been forged down to a square shape and later will be forged into a round shape. After coming from the mold, the ingot has been subjected to a careful chemical analysis to determine its fitness for use as a gun barrel.] [Illustration: A 9,000 TON HYDRAULIC FORGING PRESS IN THE PLANT OF THE MIDVALE STEEL CO. This press is needed for such large caliber guns as the 14-inch and 16-inch guns. The piece of forging under the press is armor plate and not a gun forging.] [Illustration: THREE TUBES OF THE 155-MILLIMETER GUNS SUSPENDED AT FURNACE. Three tubes of the 155-millimeter guns suspended at furnace ready for heating and quenching to give them the necessary combination of hardness and toughness. The door of the furnace is open. The tubes remain in this furnace for perhaps eight hours at a temperature of 1,500° Fahrenheit or until a bright yellow color, uniform in every part.] [Illustration: A TUBE FOR A 12-INCH GUN JUST OUT OF THE FURNACE, WHERE IT WAS TEMPERED AT WHITE HEAT AND IS NOW READY FOR QUENCHING IN THE PLANT OF THE MIDVALE STEEL CO. The gun tube is 41 feet long.] [Illustration: TUBE OF A 155-MILLIMETER GUN BEING TURNED, PRIOR TO BORING, AT THE TACONY ORDNANCE CORPORATION PLANT.] [Illustration: TUBE OF A 155-MILLIMETER GUN IN A LATHE BEING BORED. The ingot out of which this tube was made, came from the mold in an octagonal shape and later was forged into a square shape and finally made round. It now, too, has the hole bored partially into it. Through this hole, ultimately, will pass the projectile.] The forging press used for the larger caliber guns, such as 14-inch and 16-inch, is of a 9,000-ton weight capacity. After the ingot forging has been reduced from squareness to a cylindrical shape under the press, it is allowed to cool, then taken to the machine shop, where it is turned and the hole through which the projectile ultimately will pass is bored into it. This hole is somewhat smaller than the diameter of the projectile, because in the finishing operation, when the gun is assembled finally and put together, the hole must be within one-one-thousandth of an inch of the diameter required, which is all the tolerance that is allowed from the accuracy to which the projectiles are brought. Otherwise the accuracy of the gun in firing would be injured and the reliability of its aim would not be satisfactory.