LEAD-COVERED PAPER-INSVLATED TELEPHONE CABLE 445 



tributer plate and the entrance point of the cable to the capstan. The 

 finished cable is taken up on reels capable of carrying three times as 

 much cable as the core trucks used with the concentric stranding 

 machine. These reels of cable are then handled through subsequent 

 manufacturing processes by electric trucks. 



Fig. 14 — Cabling machine. 



The principal advantages of this construction are that slightly less 



copper and paper are required in large sizes of cable due to the shorter 



lay in the outer strands. With the same investment in machinery and 



building, a much larger production may be obtained. Much finer 



gauges of wire may be stranded without danger of stretching beyond 



its elastic limit. 



Vacuum Drying 



Dry paper is an excellent insulation for the conductors of a telephone 

 cable, but it must be bone dry. Dry paper takes up moisture rapidly 

 and 1000 lbs. loosely packed in a few hours will absorb 90 lbs. of 

 moisture in a room at summer temperature and 60 per cent relative 

 humidity. 



A vacuum drying operation is applied to stranded cable prior 

 to the lead sheathing operation at a temperature of 270° F. for a period 

 of from 12 to 42 hours, depending on the size of cable. The vacuum 

 maintained toward the end of the drying cycle is less than 2 in. Hg. 



The vacuum drying system installed at the Point Breeze plant has 



