1. The passive needle can't stop in the arbitrary position very well, and does not coincide with the main needle. The cleaning method is to remove the dial glass, adjust the pressure spring screw of the passive needle, and adjust the pointer to make it coincide with the main needle.

2. After the sample is fractured, the pendulum falls back quickly, forming impact. The first thing is that the buffer does not work properly. In addition to adjusting according to the usual practice, we should also consider whether the oil is too thin or too dirty.

3. In the tensile test, the fracture of the sample is always broken on both sides. For the reason of this kind of scene, we should first consider whether the local device of the main body of the testing machine is vertical or not. If this reason is removed, the following three aspects should be removed.