Rock Testing Hammer

The RockSchmidt is the world’s most advanced rebound hammer fully adapted specifically to the extremely varied rock testing applications.

The RockSchmidt incorporates statistical methods based on ASTM and ISRM recommendations and provides the user with the freedom to define his own statistical process for determining a rebound number.

Type N with standard impact energy ist most suited to field testing.
Type L with low impact energy as specified by ASTM for testing cores.


The features of the hammer make it ideal for rock testing applications:
* Impact Angle Independence: The rebound value is independent of the impact direction.
* Optimized for Field Work: Tighter sealing against dirt and dust intrusion for longer life. Significantly lighter and more ergonomic than the classic Schmidt hammer. A large number of readings can be saved and downloaded later to a PC.
* Preset Statistics: Statistics methods recommended by ISRM and ASTM are implemented into the hammer for automatic calculation of the rebound number. The option is also there to define a user specific statistics method.
* Unconfined Compressive Strength: ISRM recommends a correlation between UCS and the rebound value based on the formula
UCS = aebR (where R is the rebound value). A correlation in this format may be defined in the PC software and downloaded onto the RockSchmidt.
* E-Modulus: ISRM recommends a correlation between elastic modulus and the rebound value based on the formula Et = cedR (where R is the rebound value). A correlation in this format may be defined in the PC software and downloaded onto the RockSchmidt.
* Weathering Grade: Impacting on the same location twice can be used to correlate to weathering grade. The ISRM recommended method has been included in the device.

  • Geomorphological applications which investigate the bulk hardness properties of a rock outcrop
  • Prediction of weathering grades
  • Correlation to Unconfined (or Uniaxial) Compressive Strength (UCS)
  • Correlation to Young’s Modulus
  • Prediction of penetration rates for tunnel boring machines and rotary drum cutters
  • Testing on cores and blocks

Technical Data

Impact energy (N) 2.207 Nm, (L) 0.735 Nm
Hammer mass 115 g
Spring extension 75 mm (2.95")
Plunger radius 25 mm (0.98"
Dimensions of housing 55 x 55 x 250 mm (2.16" x 2.16" x 9.84")
Weight 570 g

Memory Data

No. of impacts in a series Maximum 99
Memory capacity dependent on length of test series
Example 400 series with 10 values per series
Example 200 series with 20 values per series

Electrical data

Display 17 x 71 pixels; graphic
Battery lifetime >5000 impacts between charges
Charger connection USB type B (5V, 100 mA)
Environmental conditions
Operating temperature 0 to 50°C
Storage temperature -10 to 70°C