Results of this pole line study showed that left spiral occurred about three times as fre- 

 quently as right spiral. Generally, the pole twisted in the same direction as the spiral and the 

 few exceptions were believed to have been due to line pull. Left-spiraled poles seemed to dis- 

 tort more than right -spiraled poles. However, extreme distortion was always associated with 

 severe spiral grain on the pole's surface. Many poles showed spiral grain on the surface but 

 did not twist in place; this indicated that seasoning might have reduced the distortion forces. 



The effect of seasoning on the three lines for which information was available is shown in 

 the following comparison: 



Air Proportion of poles 



Transmission 



line 



1 

 2 

 3 



seasoning 



period 

 (Months) 





 6 



22 



with distortion greater than 

 3 percent ^ 

 (Percent) 



26 

 22 

 2 



^In percent of pole circumference at ground line. 



On some individual poles, the spiral angle was not the same along the entire length. No 

 correlation could be established between the change of spiral angle and the pole's distortion. 

 However, the relation between the average degree of spiral grain and the amount of distortion 

 was definite; as the average degree of spirality increased, the amount of distortion increased 

 (table 1). 



Table 1. - -Relation of distortion to spiral grain classes in four transmission lines 







Left 



-spiraled grain 



: Right 



-spiraled grain 



: Right -spiraled ^ 



grain 



Spiral ratio 



. Left distortion : 





: Left distortion : 





: Right distortion : 







class 



: in degrees : 



Total 



: in degrees : 



Total 



: in 



degrees : 



Total 







: 0-5 



: 5-10 : 





: 0-5 : 



5-10 : 





: 0-5 



: 5-10 : 

















Number 











1 



1- 10 



7 



9 



16 



























1 



11- 20 



26 



5 



31 



1 







1 



4 







4 



1 



21- 30 



20 



2 



22 



5 







5 



6 







6 



1 



31- 40 



17 



3 



20 



4 







4 















1 



41- 50 



17 



1 



18 



3 







3 



6 







6 



1 



51-100 



28 



3 



31 



9 







9 



14 



1 



15 



1 



101-150 



20 







20 



3 







3 



5 







5 



1 



.151-200 



7 







7 



3 







3 



2 







2 



1 



.201+ 



23 







23 



1 







1 



5 







5 



No spiral 



25 







25 















1 







1 





Total 



190 



23 



213 



29 







29 



43 



1 



44 



In terms of 1 inch of deviation for indicated inches measured along the longitudinal axis of 

 the pole. For example, 1:10 means 1 inch of grain deviation in 10 inches along the longitudinal 

 axis of the pole. 



^ As used in this paper, "left spiral" means that as you face an upright pole, grain spirals 

 to the left as you look from the bottom to the top of the pole . 



3 



