: WOOD PIPE FOR CONVEYING IRRIGATION WATER. 25 
The thickness of the staves varies to some extent. The redwood 
pipe in usual sizes is about 1 inch thick and the fir pipe 14 inches. 
The eastern pipe is usually 1% inches thick, while for pressures of 40 
pounds or more and in sizes from 24 inches up, the shell of some of it 
is made 3 inches thick. 
Galvanized steel wire is used exclusively on the Pacific coast for 
banding. The size of the wire varies from No. 8 to No. 0, and the 
closeness of wrapping is regulated according to the pressures for 
which the pipe is designed. These may range from very low heads 
up to 400 feet or more. The eastern factories band their pipes with 
hot rolled steel 14 or 16 gauge, 1 inch wide, and No. 16 and No. 18 
gauge, 14 inches wide. The banding is done with a machine which 
imposes on the steel a tension sufficient to make a very tight contact 
with the wood, and may even indent the staves somewhat where wire 
is used. The ends of the bands are secured with staples or clips. 
After the pipe is banded and the ends are milled for couplings, 
each section is dipped in a hot asphaltum preparation which thor- 
oughly coats the bands and exterior of the pipe, then it is rolled in 
sawdust or shavings to form an outer-covering, which renders it more 
agreeable to handle. 
COUPLINGS. 
Couplings for machine-banded pipe are of several types. Of these 
one of the commonest is the “inserted joint.” To make this cou- 
pling a tenon is milled on one end of a section of pipe and a mortise 
on the other, so that the connection is made by simply inserting the 
tenon of one section into the mortise of another and driving together. 
In the western pipe this form of coupling is used principally for low 
pressures. Where greater strength is required reinforcement may be 
applied to this joint by using individual bands. For another form of 
coupling tenons are made on both ends of each section of pipe, and 
with each joint a wooden stave collar or sleeve is used, into which the 
tenons are inserted. These collars for small pipes are machine 
banded the same as the pipe, but for the larger sizes individual bands 
are used. Collars of riveted steel or iron were used with such pipe 
in the earlier days of its manufacture on the Pacific coast, and cast- 
iron collars have been employed also in many places. The latter 
material is still used for bends, crosses, tees, reducers, and other 
specials, but for collars it has been almost wholly supplanted by the 
other forms mentioned. The wooden collars are cheaper, but because 
they often decay quickly are much inferior to those made of iron. 
USE OF MACHINE-BANDED WOOD PIPE. 
Machine-banded wood pipe has had its most extensive use in the 
Pacific coast and Rocky Mountain States for municipal waterworks 
systems, where there is scarcely a city or town of any consequence 
