Mechanical thermometer error sources have?

Mechanical error of the thermometer mainly comes from the following several reasons: 1. The accuracy grade of the thermometer itself, high grade, the relative error is much smaller. 2. Heat pipe is sheath maerial of insertion depth, the depth must be original over the temperature of the thermometer, usually will have a sheath maerial pits, liquid to flow over the pits. 3. Thermal sheath maerial of material, different material heat of reaction time and cooling degree is different, can lead to precision error is different. 4. Whether the thermometer with a sheath, sheath thickness and material of different can also lead to the reading error of the thermometer and reaction time. 5. Using the environment also can affect. Mainly is the five aspects, you have know some more?