The Barcol Impresser is a simple instrument with very little to go wrong. The indenter point is usually the most vulnerable part becoming worn or damaged in use. Usual symptoms are that readings are much higher than expected and it becomes impossible to achieve calibration. The indenter points are easily changed but cannot be repaired or reground. The GYZJ 67 indenter point is only used in the Barcol 936 impresser. This has a different angle to the indenters used in the 934-1 and 935 impressers which share the GYZJ 6-5 indenter point.
