Technical parameters.
1、Accuracy: ±2.5%
2、Working environment temperature: 5～50℃
3, the maximum load: 980g
4, the pointer points to 100 and restore the zero tolerance: ± 1 grid scale
5、Exterior size：71×48×29（mm）
Before use, push the indenter with your finger three times to check whether the pointer is pointing to 0 position, when the pointer is not at 0 position, turn the cover ring to align the pointer to 0 position.
When using, hold the hardness tester vertically downward so that the contacts are aligned with the surface of the sand type (core) to be measured, and press downward to make the contact plate close to the surface of the sand type (core), while pressing the locking pin, let the pointer stay in the indicated position, and visually read the value. Then release (reverse pressure) pin tight pin, so that the method, in the same measurement site for three consecutive measurements, calculate the average value, that is, the surface hardness value of the site.