We use a fully automated screw driving sounding (SDS) machine that can do both Swedish Weight Sounding (SWS) and Screw Driving Sounding (SDS) tests. The rig is transported in a small van and moved around on site busing a small tracked crawler unit. The machine can be operated from the tracked unit or can be used independently.

The unit operates on a 100 volt system with power supply by means of a small petrol generator. The main unit is mounted on a mast and moves up and down during the test by means of an electric motor. This motor is used to apply load to the rods. Another electric motor is used to rotate the rods. The machine is operated using a separate control unit, which also electronically records the information measured in the test.

The SDS is a quick and relatively inexpensive test that is done with fully automated lightweight equipment that can access almost any site. The test can give an indication of soil type and soil properties. The SDS is best used in conjunction with CPT testing (or other testing) so as to create site specific correlations.


The screw driving sounding machine has been modified to undertake the following in situ testing:

  • SWS / SDS

The maximum depth capacity for in situ testing is 10m +.

Weights and Dimensions

On tracked crawler:

Height: 1.2 m (mast down), 1.7 m (mast fully up)
Length: 1.4 m
Width: 0.7 m

Off tracked crawler:

Height: 1.3 m (mast fully up)
Length: 0.75 m
Width: 0.45 m