The paper analyzes the characteristics of the experiment well and the special con- nection form of the FRP wound! well pipes,and it is a new idea that the taper trapezium threads are used as the connection,the paper also describes in detail the design of FRP wound well pipe itself and the taper trapezium threads that can bear 2～8×10~4N function force from the axial di- rection.

With the development of industry,there are more requirements of accaracy of taper thread plug gauge s manufacture.

Non-damage measurement on internal taper thread of electrode;

Measurements of non-contact external tapered thread based on linear array CCD;