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< prev - next > Energy Hydro power a simple height and depth measuring instrument (Printable PDF)
Measuring tall objects is a
requirement which may arise from
time to time in various fields of
science and technology.
Unfortunately, most types of
apparatus which give direct
readings are expensive to buy,
particularly when one takes their
infrequent use into account. The
surveying instrument described in
this article can be easily made and
is inexpensive as the materials used
in its construction are readily-
1 wooden 12" rule
1 strip of thin, flexible
wood, of similar size
Another strip of wood, 8"
long x 1/8" thick and about
the same width as the rule
Two small wood screws
1 thin piece of card
1 length of thin string
attached to a small weight
to make a plumb bob
A small set-square.
Figure 1: Parts of the measuring instrument.
1. Cut the flexible strip to the same shape as the ruler and the 8" x 1/8" strip to the same
2. Cut the thin card into a square so that the length of its sides is equal to the width of
the ruler.
3. Clamp these three parts to the ruler in the following order. First the card which should
fit flush at the zero end of the ruler. Next, the flexible strip which must lie along the
back of the ruler. Lastly, the 8" x 1/8" strip set at an angle of 90° to the top of the rule
and attached at the zero end. This is all illustrated in Fig. 1.
4. Screw this assembly together with two small screws which can be countersunk either
from the front or the back. Wood glue may be additionally used
between the layers if desired.
5. Place a set-square along the top of the rule, line up its vertical side with the zero mark
on the rule and draw a line running up the vertical strip. Mark points on this line at
intervals of half-an-inch (Fig. 2).
6. At each of these points, drill a small hole in the vertical strip and mark each alternate
hole 1, 2, 3, etc., to correspond with the inch graduations of the rule.
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