Product Manual

7
PLUNGER RELEASE
When using the Clegg, the Plunger Release can be used to provide consistent drop
distance. Place palm of hand against the handle and grasp the spring plunger knob
between the index and middle finger. Pull the knob to retract the pin from inside the tube
and raise the hammer so the white line mark is above the top of the tube guide.
Release the knob and rest the bottom of the hammer on the plunger pin inside the tube.
When ready to open plunger knob release the hammer, place the palm of hand against
the handle, grasp the spring plunger knob between the index and middle finger. Pull the
knob back to retract the pin which releases the hammer to drop.
NOTE: The hammer release spring plunger can be locked out of the guide tube by pulling back the knob and rotating the
knob 90 degrees while the pin is retracted. To unlock the spring plunger, rotate the knob until the key in the knob aligns
with the slot in the shaft and the plunger pin springs into the guide tube.
Performing a Clegg Impact Test
IMPACT CONTROL – Testing Athletic Fields
The suggested protocol for performing a Clegg Impact Test (CIT) for surfaces where Impact Control is
the goal is a one-drop protocol. Impact Control is used in situations where soft surfaces and hard
surfaces could result in the decline of performance and the increase in injuries (athletic fields,
racetracks, tennis courts, golf courses, etc.). These surfaces are exposed to routine maintenance
such as Aerification, topdressing and other leveling steps with the intent of producing a finished
product which falls within a specific range or window of impact values (not too soft and not too
hard).
Typically, the 2.25 kg hammer models are used for Impact Control. Additionally, impact values noted
in literature for natural and synthetic turf are often displayed in gravities (G’s). NOTE: There are 10
G’s “gravities” per 1 CIT unit.
Set up appropriate Impact Control test parameters in Clegg Control app. See the Test Setup section on
page 13 for more detailed app setup instructions.
CUSTOM PROTOCOLS
Based on an examination of literature, different protocols have been used to target different
surface and subsurface characteristics. These custom protocols (different number of drops,
variations in drop height, peak impact value, or average impact value) can be effective when
consistently used across an area. If an area tested results in readings that are consistently close to
the maximum reading values of the Clegg, a shorter drop height might be considered in order to
get a more meaningful result. Be sure that is a modified drop height is used, the impact tester
missile is marked with a line showing this drop height and each subsequent test in that area is
performed from this new marked drop height or results will not be comparable.
CAUTION: Do not operate hammer on concrete without the calibration pad in place as damage to the instrument may
result.
Plunger