Copyright Goodheart-Willcox Co., Inc.
166 Section 1 Preparing to Build
P R O C E D U R E
Establishing Plumb Lines
Plumb lines can be checked or established by first operating
the instrument as shown in Figure 8‑27. As you tilt the
telescope up and down, all of the sighted points are located
in the same vertical plane. To plumb structures, such as
posts or walls, follow these steps and refer to Figure 8‑28:
1. Set up the transit at a distance from the object equal
to at least the height of the object. Tilt the telescope
to sight on the base.
2. Loosen the horizontal clamp and line up the vertical
crosshair with the base of the object.
3. Tighten the horizontal clamp.
4. Tilt the telescope upward to the top of the object.
If the object is plumb, the crosshair will be on the
same plane as it is at the base.
Continued
8.5.5 Running Straight
Lines with a Transit
Although the builder’s level can be used to line up
stakes, fence posts, poles, and roadways, the transit is
more accurate for these tasks, especially when differ-
ent elevations are involved. Set the instrument directly
over the reference point. Level the instrument and
then release the lock that holds the telescope in the
level position. Swing the instrument to the required
direction or until a stake is aligned with the vertical
crosshair. Tighten the horizontal circle clamp so the
telescope can move only in a vertical plane. Now, by
pointing the telescope up or down, any number of
points can be located in a perfectly straight line. See
Figure 8‑26.
8.5.6 Vertical Planes and Lines
Beyond the leveling tasks just mentioned, the transit is
also a good instrument for these tasks: ■
■ Measuring vertical angles above or below the line
of sight ■
■ Plumbing building walls, columns, and posts
P R O C E D U R E
Measuring Vertical Angles
1. Position the instrument near the structure. Level the
instrument.
2. Release the lever that holds the telescope in a
horizontal position.
3. Swing the instrument vertically.
4. Set the horizontal crosshair at the point you wish to
measure.
5. Tighten the vertical clamp.
6. Make a final, fine adjustment with the tangent screw
to locate the horizontal crosshair exactly on the
point.
7. Read the vertical angle on the vertical arc scale and
the vernier.
A B C
Goodheart-Willcox Publisher
Figure 8‑26. How to use the transit to align a row of
stakes.
C
B
A
Goodheart-Willcox Publisher
Figure 8‑27. A transit can be used to lay out or check points
in a vertical plane.
90°
Goodheart-Willcox Publisher
Figure 8‑28. Using the transit to plumb an object. First,
align the vertical crosshair with the base. Then, swing the
telescope to or near the top. Adjust the object for plumb as
needed. Reposition the instrument at a 90° angle to the first
line and repeat the process.
166 Section 1 Preparing to Build
P R O C E D U R E
Establishing Plumb Lines
Plumb lines can be checked or established by first operating
the instrument as shown in Figure 8‑27. As you tilt the
telescope up and down, all of the sighted points are located
in the same vertical plane. To plumb structures, such as
posts or walls, follow these steps and refer to Figure 8‑28:
1. Set up the transit at a distance from the object equal
to at least the height of the object. Tilt the telescope
to sight on the base.
2. Loosen the horizontal clamp and line up the vertical
crosshair with the base of the object.
3. Tighten the horizontal clamp.
4. Tilt the telescope upward to the top of the object.
If the object is plumb, the crosshair will be on the
same plane as it is at the base.
Continued
8.5.5 Running Straight
Lines with a Transit
Although the builder’s level can be used to line up
stakes, fence posts, poles, and roadways, the transit is
more accurate for these tasks, especially when differ-
ent elevations are involved. Set the instrument directly
over the reference point. Level the instrument and
then release the lock that holds the telescope in the
level position. Swing the instrument to the required
direction or until a stake is aligned with the vertical
crosshair. Tighten the horizontal circle clamp so the
telescope can move only in a vertical plane. Now, by
pointing the telescope up or down, any number of
points can be located in a perfectly straight line. See
Figure 8‑26.
8.5.6 Vertical Planes and Lines
Beyond the leveling tasks just mentioned, the transit is
also a good instrument for these tasks: ■
■ Measuring vertical angles above or below the line
of sight ■
■ Plumbing building walls, columns, and posts
P R O C E D U R E
Measuring Vertical Angles
1. Position the instrument near the structure. Level the
instrument.
2. Release the lever that holds the telescope in a
horizontal position.
3. Swing the instrument vertically.
4. Set the horizontal crosshair at the point you wish to
measure.
5. Tighten the vertical clamp.
6. Make a final, fine adjustment with the tangent screw
to locate the horizontal crosshair exactly on the
point.
7. Read the vertical angle on the vertical arc scale and
the vernier.
A B C
Goodheart-Willcox Publisher
Figure 8‑26. How to use the transit to align a row of
stakes.
C
B
A
Goodheart-Willcox Publisher
Figure 8‑27. A transit can be used to lay out or check points
in a vertical plane.
90°
Goodheart-Willcox Publisher
Figure 8‑28. Using the transit to plumb an object. First,
align the vertical crosshair with the base. Then, swing the
telescope to or near the top. Adjust the object for plumb as
needed. Reposition the instrument at a 90° angle to the first
line and repeat the process.