room temperature. The joint is then ready for insulation with K580 

 splicing tape. This tape should be prestretched and released during the 

 application to avoid residual tension in the completed insulation joint. 

 The tape is used to build up the joint to approximately the diameter of 

 the original insulation over the conductor. The joint is then covered 

 with one layer of polyvinyl chloride tape with some overlap. Three 

 layers of neoprene tape are wound over the polyvinyl chloride tape, after 

 which the joint is ready for protective coverings. 



Injection-Molding Method . The method described above is perhaps 

 the simplest, and has been used by the telegraph cable companies in their 

 ordinary repairs to telegraph-tyne cables. However, because of the more 

 critical nature of the transmission characteristics of wide-frequency 

 telephone-type cables, and also because of their high voltage, this 

 method has not been generally used in telephone cables. Instead, the 

 conductor joints are insulated with an injection-molding machine. 



In this process the conductor joint is made by brazing, and the con- 

 ductor is then held inside a carefully machined mold into which molten 

 polyethylene is injected at high temperature and pressure. After the 

 polyethylene has filled all the voids between the cable and the inner 

 surfaces of the mold, the temperature is lowered and the mold is re- 

 moved, leaving the polyethylene insulation neatly fused into the balance 

 of the cable insulation. After the feather edges which appear at the 

 mating surfaces of the mold halves are smoothed down with a sharp knife, 

 the final produce is practically a homogenous transition from conductor- 

 joint insulation to basic-cable insulation. 



The dies for the molding heads are machined to meet the outer dia- 

 meter under the basic cable insulation; hence, different dies are re- 

 quired for each size of cable core. The joints are generally x-rayed 

 for possible inclusion of foreign matter and voids. This method produces 

 a result equivalent to a factory-made joint. It is, however, somewhat 

 slower than the universal method described above and requires special 

 equipment. 



Splicing 



Splicing is joining the armor wires of two lengths of armored cable 

 in such a manner that the full tensile strength of the cable can be 

 passed from one length to the other. The method generally followed in 

 replacing the armor is referred to as the "overlapping splice". In pre- 

 paring for the conductor joint (see above), 40 feet of sheathing and jute 

 yarn are unlaid on one end and 8 feet are unlaid on the other. These 

 unlaid portions will be referred to as the "long end" and "short end", 

 respectively. 



The jute yarn on the short end is wrapped round the core and secured 

 with yard seizings. Any remaining bare core should be wrapped with the 

 jute yarn from the long end. The short-end sheathing wires are then 

 laid spirally over the jute bedding, with all wires abreast in their 

 correct order and secured with yarn seizings at about 1-foot intervals. 

 Next, the long-end sheathing wires are laid on spirally, overlapping the 



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