WELDING BARRELS. 443 



WELDING BARRELS. 



The process for making common gun-barrels is very simple, and 

 is done in the following manner: — A bar of iron is heated and 

 hammered out into a thin flexible rod, resembling a good-sized 

 hoop, of a length and thickness proportionate to the size and 

 weight of the intended barrel. This rod is beat thinner at the 

 muzzle-end than it is at the end intended for the breech. 



This being arranged, the hoop is heated and turned round a 

 mandrel, (a rod of tempered iron much smaller than the intended 

 bore of the gun,) Avith the edges overlapping each other the half of 

 an inch or so, and when welded together the barrels have the ap- 

 pearance of being manufactured or bored from a solid rod of iron. 

 After being turned round the mandrel, the overlapping joints of 

 the hoop are welded together by heating three or four inches of 

 the tube at a time, and beating upon an anvil furnished with several 

 semicircular furrows suitable for the various-sized barrels that are 

 manufactured. This is the modus opei^andi adopted for forging 

 common barrels, such as are used for exportation, and of which 

 trash immense quantities come to this country through the hands 

 of our hardwaremen. 



The forging of stub-twist barrels and other barrels of a better 

 description is quite a different operation, and requires far more 

 labor and skill. The rod of iron is first heated to a red heat, a 

 few inches at a time, and, one end being made stationary in a vice 

 or other suitable contrivance, the other is seized by an instrument 

 with a handle similar to an auger, by means of which it is twisted 

 round a bar of iron (the mandrel) much smaller than the intended 

 bore. By this operation the fibres of the metal are twisted in a 

 spiral direction, which arrangement is known to resist the explosive 

 force of powder much more than when the fibres all run longitudi- 

 nally. The hoops or rods of the best stub-twist are generally about 

 half an inch or less in width, and consequently there will be over two 

 spirals in every inch of barrel, when the twisting process is com- 

 plete, as the joints are not made to overlap each other, but are forced 



