232 



ENGINEERING ON THE FARM 



WZJ7JW777Z 



60dp . ipikes \ 



o I— J, * 



Fig. 195. Method of anchoring posts 



on low depressions where there is 



a tendency for the wire to pull 



the post out of the ground 



them to settle and become solid. The best time of the 

 year is after the frost has left the ground in the spring. The 



brace timbers used should be 

 4 by 4 inches by 12 feet, and 

 the ends should be spiked to 

 each post with two 60-penny 

 spikes. Wire braces should be 

 two strands of No. 8 soft wire 

 twisted together. 



Concrete posts. The rapidity 

 with which wood posts decay 

 and the increasing cost of 

 timber have led to the use of 

 some other materials for posts. 

 Concrete posts (Fig. 196) are 

 of two kinds, solid and hollow. 

 The only object in making a 

 post hollow is to save material 

 and decrease weight. The hollow posts are the more expensive, 

 because additional time is required in fitting an inside form 

 and in arranging the reinforcement. There is some ques- 

 tion as to their durability as compared with solid posts. 

 Solid posts may be made with a dry mix tamped into the 

 mold or with a wet mix poured. The mold should not be 

 removed in either case until the post has cured sufficiently 

 to stand handling. With a wet mix, one post a day is all 

 that can be made in a mold. The best mix is 1:2:3, 

 thoroughly mixed. The reinforcement should be placed 

 approximately three-quarters of an inch from the surface. 

 The reinforcing material should be sufficiently rough to 

 form a bond with the concrete. In using smooth, cold- 

 drawn wire, it has been found to be an advantage to wash 

 it with a strong caustic solution or to treat the wire with 

 a diluted solution of salammoniac, which slightly rusts it. 

 Concrete posts are permanent when well reinforced and 

 the reinforcement is so placed that the strain will come 



