1、 The use method and working principle of the dual purpose fixture for machining the outer and inner spherical surfaces The use method and working principle: firmly clamp the main body on the square tool rest of the lathe, so that the upper tool tip of the lower bar is in the same plane with the axis of the lathe spindle. The tailstock taper handle 7 is inserted into the tailstock taper hole of the machine tool. The center distance between the two pin holes of the connecting rod 5 is equal to the spherical radius of various sizes to be machined. When machining the inner spherical surface of the valve body, use the pin 6 to connect the connecting rod 5 of the required size to the lower rod 4. After the tailstock is adjusted and fixed, the inner spherical surface can be turned out by the horizontal automatic tool feeding of the middle carriage (or the manual tool feeding of the middle carriage). When machining the outer spherical surface of the valve core, connect the connecting rod 5 with the tailstock taper handle 7 of the upper rod 2. Adjust and fix the distance of tailstock. When the middle carriage is in cross feed, the upper rod 3, under the action of the connecting rod 5, moves longitudinally with respect to the main body 1 (when the middle carriage moves from the outside to the inside, the upper rod 2 moves forward with respect to the main body 1; on the contrary, it moves backward) and drives the pinion 3. The pinion drives the lower rod 4 to move in the opposite direction with the upper rod 2. After combining with the cross feed motion of the middle carriage, the outer spherical surface is turned out. The longitudinal feed and cutting depth of the inner and outer spherical surfaces are controlled by the hand wheel feed of the tailstock.

How to measure the plastic coated pneumatic butterfly valve
First of all, we must understand three basic concepts, one of which is its shrink length. This mainly refers to the length when the product is shrunk to the maximum. Such measurement results can show the product's shrink ability. Generally speaking, the higher the shrink ability, the more guaranteed the quality. Another concept is that according to the length, It refers to the length of the middle position of the maximum displacement. In addition, we want to say the stretching length of the pneumatic butterfly valve, which is the length of the product when it is stretched to the maximum.
When we stop measuring, we often use a relatively common measuring method, that is, directly fix the ruler on the plastic coated pneumatic butterfly valve, and then cut off the excess part of the ruler after measuring. Although this is a waste, it can accurately show its length. So, this is actually a relatively common way.