Toro 4045 Operator's Manual page 54

Given the above information, you can calculate the number of
rods required to reach your beginning point at the appropriate
depth. Toro recommends that you start the entry point the
same distance back from your beginning-at-depth point as
the length of pipes you will need to reach that point. This will
ensure that you have enough extra space so you will not need
to over-steer and damage the pipes.
1. 26% pitch
2. 76 cm (30 inches)
3. 142 cm (56 inches)
•
Begin steering up for the next 3 m (10 ft), pushing the
pipes in at the maximum pitch change of 8%. This results
in a change of pitch from 26% at the beginning of the 3 m
(10 ft) to 18% at the end of the 3 m (10 ft) for an average
pitch of 22%. Given that, the drill head lowers another 66
cm (26 inches) and is now 142 cm (56 inches) deep.
•
Continuing steering up for the next 3 m (10 ft) at an 8%
pitch change, your pitch will change from 18% to 10%
for an average pitch of 14%. Given that, the drill head
lowers another 43 cm (17 inches) and is now 185 cm (73
inches) deep.
•
Continuing steering up for the next 3 m (10 ft) at an 8%
pitch change, your pitch will change from 10% to 2% for
an average pitch of 6%. Given that, the drill head lowers
another 18 cm (7 inches) and is now 203 cm (80 inches)
deep.
•
Leveling the drill head from 2% to 0% takes less than 1.5
m (5 ft) more for a final depth of 208 cm (82 inches).
Reaching this final point took 4-1/2 pipes 3 m (10 ft)
long. So for this example, your entry point should be 14.7
m (45 ft) back from the beginning-at-depth point of your
installation.
The following example illustrates the process given an
installation using the maximum entry pitch of the machine
(26%) on level ground:
•
Figure 55
4. 185 cm (73 inches)
5. 203 cm (80 inches)
6. 208 cm (82 inches)
54
Insert the first 3 m (10 ft) of drill bit/pipe into the ground
with no steering. The end of the drill bit will be 76 cm
(30 inches) deep (Figure
7. 14.7 m (45 ft)
52).