The pressure spring determines how much pressure is applied to the indenter point, and how deeply the point penetrates into the test specimen. With time the spring can become compressed and coil bound, especially if over-tightened to compensate for worn or damaged indenter points. The GYZJ-3 spring is only used in the Barcol #934-1 impresser. The GYZJ-3 may be replaced with the AYRS-146 spring to convert the gauge to to 935 impresser. (Calibration Disk GYZJ-069 also required.) Relaxed length when new: 23.8 millimetres or 0.937"
