Three Wolf probes are used for inspecting the
GTE are less than 7 inches from the inspection
LM2500 GTE (fig. 3-27). Each probe has a unique
ports). Although all probes have been made to
configuration that has special capabilities. The
the same specification, some variance in the
parameters that are varied to achieve these proper-
magnification factor is provided by the Wolf and
ties are the viewing angle, the field of vision, and
Eder No. 1 probes. The Eder probe has a
the magnifying factor. Understanding the
magnification factor of 1:1 at 5 inches instead of
capabilities of each probe will help you find out
at 7 inches. Eder is working to standardize their
the best way to use it. The numbering of the
probe. However, the user should be aware that
probes has nothing to do with their importance
it is an Eder and verify the optical characteristics
or the sequence in which they are used.
of the probe in his kit.
Figure 3-27 provides parameters that define
Probes No. 2 and No. 3 are identical with the
the probes. A quick review of these parameters
exception that No. 2 is looking down (100 from
reveals the characteristics of each probe. Probe
axis of probe) and No. 3 is looking up (70 down
No. 1, with a 90-degree direction of vision, has
from axis of the probe). Objects 2 inches away
a narrow field of view and a high magnification
from the ends of these probes appear at their true
factor. The magnification factor of 1:1 at
size. Objects closer than 2 inches appear
7 inches means that an object 7 inches away can
magnified, and objects further than 2 inches
be seen as true size, but objects closer than 7
appear reduced. The advantage of these probes
inches can appear magnified. This probe is very
is that they have a wide view and are suited for
searching. They also have a large depth of field
difficult to use for searching for an object because
of its narrow field of view. Also, its short depth
which does not require constant refocusing. With
of field requires constant refocusing. The
these probes, all objects 1/4-inch distance from
important feature of probe No. 1 is its ability to
the probe tip to infinity will be in focus.
provide greater magnification to an object already
The direction of view is always given in
identified (most inspection areas in the LM2500
degrees. Some manufacturers consider the
Figure 3-27.--Probe used with Wolf borescope.
3-19
