Abstract: Modified apparatus for testing the adhesive strength of the bond between the liner and medium in corrugated paperboard in which a clamp is used having a plate 24 abutting one liner and fingers or prongs 21 holding the medium and liner against the plate 24. The bond between the medium and the other liner is measured by applying a force to a strip bonded to the other liner and measuring the applied force which results in failure of the bond. The sample preparation required is simplified with this design which avoids the use of hooks penetrating the sample.