SPRAY IRRIGATION. 37 



drilling for the nozzles. Where pipe posts are used, the pipe can be 

 held in place for drilling by wrapping a* tight wire twice around the 

 posts, then looping the wire around the nozzle pipe line so that the 

 pipe will hang several inches below where it is attached to posts. 

 The pipe is then fastened rigidly so that it can not turn while being 

 drilled. A good way to do this is to replace the handle in the turn- 

 ing union with a 10 or 12 foot length of f-inch pipe, so that one end 

 will rest on the ground, acting as a wrench holding the entire line. 

 The nozzle holes are then spaced with a stick cut the proper length 

 and marked with crayon. Three to four feet is the usual distance 

 between the nozzles. 



The nozzle holes must be in a straight line along the shell of the 

 pipe. To accomplish this a special drilling machine is used. This 

 machine hangs on the pipe and can be set in a perpendicular position 

 by means of an attached level bubble. It is securely clamped for 

 each drilling and the hole is made on the lower side of the pipe. The 

 shank of the drill is a thread tap, so that the hole is threaded by run- 

 ning the drill into the pipe at the completion of the hole. Lard oil 

 only should be used on the drill, as mineral oils cause the metals to 

 heat and pinch the drill. A drop or two of oil placed on the upper 

 side of the pipe will run to the lower side and be sufficient for each 

 hole. 



When the drilling of a line is complete the pipe is placed in its 

 permanent supports and connected to the feed pipe. It always is 

 desirable to run the water through the lines before screwing in the 

 nozzles. This will wash out all the foreign materials in the pipe, 

 and the nozzles can be put in at any time. When the water is first 

 pumped through after the nozzles are in place, the end of the pipe 

 should be left open for a time and each nozzle inspected. Scales or 

 dirt in a nozzle can be dislodged by striking the opposite side of the 

 pipe a sharp blow with a hammer while a finger is placed over the 

 nozzle. A small wire thrust into the nozzle and quickly withdrawn 

 also assists in removing obstructions. 



COST DATA. 



Cost data for material can be given only for general estimating 

 purposes, as the markets fluctuate and the prices must vary also 

 with the freight to different points. 



Manufacturers have a standard list of prices on pipe and fittings 

 from which discounts are given, according to the condition of the 

 metal market, freight rates, and size of order. The standard lists 

 are given in Table 7, with the probable range of discounts based on 

 Pittsburgh. Pa. 



