Figure 182.—Speed Timers. Two styles. The point is held against the center of the shaft to be tested. The number of revolutions per minute is shown in figures on the face of the dial. The indicator is timed to the second hand of a watch.
Figure 183.—Building Bracket. Made of 2 x 4 pieces put together at right angles with diagonal braces. The supporting leg fits between the four diagonal braces.
SOIL TOOLS
Soil moisture often is the limiting factor in crop raising. Soil moisture may be measured by analysis. The first step is to obtain samples at different depths. This is done accurately and quickly with a good soil auger. Other paraphernalia is required to make a careful analysis of the sample, but a farmer of experience will make a mud ball and form a very good estimate of the amount of water in it.
Figure 184.—Diagram showing how to cut a plank on a band-saw to form a curved rafter. The two pieces of the plank are spiked together as shown in the lower drawing. This makes a curved rafter without waste of material.