Because of the structure of scissor jack, it does not have a stable chassis. Its chassis is only a small piece, so it is faced with a problem in the selection of support points.

The supporting point of the scissor jack must meet the following two conditions. First, the position must be flat, because the base of the claw jack is not stable. If the road surface is slightly pitted or inclined, it is very likely to topple during lifting.

Secondly, the supporting point must be hard. If the supporting point of the shear jack is loose, plus the small contact surface between the shear Jack and the ground, the shear Jack will sink due to the large pressure, resulting in accidents.

Therefore, the supporting point of Jack is more important. When using shear Jack outdoors, we must do a good job in geological exploration.