Humboldt H-2987 Concrete Rebound Hammer - Manual (Page 2)

Using the Humboldt Concrete Rebound Hammer
Always hold the Concrete Rebound Hammer in both hands while in use. Also,
when in use, keep the hammer perpendicular to the surface you are testing with
the scale pointing up, making it easier to read.
Before the Hammer can be used for testing, the piston must be released out of
the hammer into the testing position. Typically during storage and transporta-
tion, the Hammer piston will be locked inside the Rebound Hammer and will
need to be released from the storage position. If the piston is not extended into
the test position, place the end of the piston against a stiff surface and gently
press the Rebound Hammer firmly against the surface. You will hear a click, and
the piston will extend into the test position.
To perform a test, make sure the piston is extended and gently press the
Rebound Hammer against the concrete surface to be tested. When the piston
is pressed all the way into the Rebound Hammer, continue to push harder until
you hear a rattling sound. Keep the Rebound Hammer firmly pressed against the
concrete surface and read the rebound number on the scale.
Figure 1: The Concrete Rebound Hammer
Figure 2: Always hold the Rebound Hammer with both hands
perpendicular to the surface