WOOD PIPE FOR CONVEYING IRRIGATION WATER, 11 



come this tendency it is now a common practice to specify additional 

 bands at the joints, and to bring all joints within a space of 2 to 

 4 feet. 



COUPLING SHOES. 



The designing of shoes is now left principally to the manufactur- 

 ers, and selection may be made from a number of patterns. Light 

 weight in most instances, where not subject to excessive corrosion, 

 is the chief consideration after strength equal to that of the bands 

 is assured. Cast-iron shoes were used principally during the earlier 

 years of continuous stave pipe building. They were heavy and 

 easily broken, and on this account common cast iron has given place 

 to malleable cast iron and steel. Malleable iron for this purpose 

 should be of the most tenacious character, capable of standing con- 

 siderable hammering without fracture. The tensile strength should 

 be not less than 40,000 pounds per square inch of section. Steel for 

 shoes should in quality be equal in all respects to that required for 

 bands. 



3SCT10N 



Fig. 1. — Kelsey joint. 



In designing butt joints,, the use of thin steel clips inserted in 

 saw kerfs is almost universal. Some variations from this form of 

 joint have been tried, however. In the "Dwelle" pipe staves were 

 tongued and grooved at the ends. In the "Wheeler" pipe a loose 

 oak tongue was used instead of a steel clip, and on a pipe at Victor, 

 Colo., clips of papier-mache were used. None of these proved satis- 

 factory. Another joint, known as the " Kelsey butt joint," is notably 

 different from the usual type. This was used on pipe lines of Provo 

 City, the Spanish Fork waterworks, and others in Utah, designed 

 by F. C. Kelsey a number of years ago, and on the Blacksmith 

 Fork pipe line built in the northern part of the State in 1912. This 

 joint (fig. 1) consists of a malleable casting which takes the place of 

 the metal clips and also fits tightly over the ends of the abutting 

 staves. It is very highly recommended by engineers who have tried 

 it, and appears to possess considerable merit. The cost is somewhat 



