Field Scout SC 900, Product Manual

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Appendix 2
Determining when to
replace the cone
Repeated soil sampling will wear down the metal cone,
especially in coarse or sandy soils. It is recommended that
the diameter of the cone be checked periodically to con-
firm that it is within the ASABE spec.
The determination as to when to replace the cone will
depend on how the user is applying the meter.
When you are doing
comparative analysis of the readings
in a field or a plot, the measurements will be consecutive.
The amount of wear of the cone will not be a factor. In
this case, it is recommended that the cone be replaced
when the shoulder is not easily recognizable as a shoulder
anymore.
If you are using the meter to get
absolute compaction
readings, replace the cone when there is a “wear factor” of
3%. Three percent wear affects the cone index
measurements by 5%. The minimum cone diameters (in
inches) are shown in table 1.
Table 1: Minimum cone diameters
The cone diameter can be checked with the depth target or
with a dial caliper or monitor.
Cone size
Cone Diameter
(new)
Cone Diameter
( 3% wear)
1/2 inch 0.505 0.490
3/4 inch 0.798 0.774