TIMBER SLIDES AND CHUTES 
265 
A common form of round timber slide has two parallel timbers 
supported on cross-skids placed from 8 to 15 feet apart. The 
timbers are from 9 to 18 inches in diameter and from 20 to 60 
feet long and are cut from trees having a minimum taper. A 
log 6 or 8 inches in diameter with a hewed face or a 4- by 8-inch 
plank may be placed between the two slide timbers and fastened 
to the cross-skids. The poles are placed from 4 to 6 inches apart 
Fig. 87. — The Terminus of a Log Slide. Idaho. 
at the base on a two-pole slide and from 8 to 15 inches apart when a 
third pole is used. The timbers usually are placed with their 
butts up grade because they sliver less, and are joined together 
by a simple lap joint. They are sunk into a skid directly be- 
neath them and fastened to it by 1 j- or 2-inch hardwood treenails, 
or |- by 12-inch iron spikes. In order to strengthen the slide 
the joints are always broken. 
On level stretches a slide is built on the ground and requires 
a minimum of bracing and support, while on steep pitches and 
in crossing depressions it is supported on crib work and is thor- 
oughly braced because rigidity is important. 
When the round logs are in place and securely fastend to the 
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