Evening Republican, Volume 18, Number 33, Rensselaer, Jasper County, 7 February 1914 — MAKING BIG CUNS [ARTICLE+ILLUSTRATION]

MAKING BIG CUNS

FROM the old-faßhioned castlron gun with a range reckoned In feet to the great gun of modern times with a range of miles is a far cry, but the resulbi of experiments by scientific men of all nations during the past *IOO years have given us today what is practically perfection in the art of gunmaking. * Over 100 years ago guns were cast in solid iron or a combination ; of bronze and iron and were always liable to explode if overcharged, due not to any fault in the material, but chiefly to the fact that they were cooled from the outside and in consequence when the gun was fired the inside or bore would expand quickly, cracking the whole piece. A later method was used by which the inside was cooled first and solidifying, was compressed and supported W the contraction of the exterior when it was cooled down. The Built-Up Gun. Still later a system of building up guns was devised whereby each portion of the metal was made to bear a fair share of the strain. Nearly all big guns are now made entirely of steel made by the open ■hearth process. Months are required to - build up one of these guns which are built in sections, i. e„ the liner or barrel, the jackets which fit over the liner and the breech block which closes the

opening through which the'projectile is thrust.

The Jackets add extra strength to the portion of the gun in which the explosion takes place. The composition of the metal varies little; the greatest care being taken to produce a metal free from bubbles. After the ingot is cast and cooled it is removed to a large furnace heated by gas or oil, securely bricked in so that very little heat is lost, and subjected to a steady flame which gradually heats it to the center.

Forced Into a Bar.

It is then taken to a press, with a pressure of 10,000 tons, where from a great block it is by degrees reduced to a long bar about 60 feet in length and two feet in diameter. This is done while the metal Is hot From the press the forging as It Is now known, goes to the wood annealing. where it is given a bath of fire entirely of wood, and brought quickie to a high temperature. This temperature is held some time after which the forging cools slowly in air.

The forging next goes to thd ma chine shop, where It is placed upon a lathe and receives its first rough machining over the outside. It is then bored to the proper size on a boring lathe. The boring is a matter of weeks and the boring bar once started requires little attention other than the changing of the cutters on the end, water running through the bar flushes out the chips and keeps the cutters from heating. When bored the forging Is known as a liner and removed to the oil annealing shop, where It is stood upright In a furnace and mafie hot with oil flames. While hot It is slowly lowered Into a pit of oil and allowed'to COOl; Absorbing the oil the metal becomes very tough., allowing, it to expand but little with the gases which force the projectiles out.

Back again to the machine shop it goes, where it is machined to the trn« size.

The jackets are made and treated in exactly the same manner, With the exception of the oil bath. When the parts are ready they are carefully fitted together and bound with hoops of brbnze or cppper. The breech of a gun is the most important part, for unless It fits perfectly the gases will leak causing back firing. Nearly all guns are rifled to give greater accuracy In firing. Rifling is a system \ot grooves in the surface of the bore which gives a rotary motion to the projectile which revolves while passing through the air, thereby lessening the resistance. A gun being entirely built 1b thoroughly polished by hand, the muzzle closed with a wooden block, the whole gun oiled to prevent weather damage and shipped to the proving grounds to be tested by the government. If up to the test requirements it is accepted and goes to help make up the armament of one of our modern seafighters.

SCENE, IN ORDNANCE FACTORY

Inspecting Breech Mechanism.