Watch the minute hand coordination, popular, is set to watch, then in view of the quasi one hour scale, minute hand away from the deviation degree “12”. At best, at the time scale for quasi one hour, minute hand coincide with the “12”. However, this is often not possible.
When the minute hand coordination bad reasons are as follows:
1, the surface of the plate installation work is bad (usually set or printing)
2, dial frame scale operator has a printing error
3, dial the center hole and movement of the hours, minutes, second hand shaft hole misalignment, claw (plate also exists between the movement and radial clearance)
4, the assembly when the minute hand when installation error
About watch, poor coordination, in the mechanical watches in the industry standard QB/T1249-2004 is such regulations: the needle and the operator centre, minute hand Angle deviation from the center of the “12” operator shall comply with such provisions. 1, classy article – 18 ~ 18 degrees (Angle); 2, grade a – 24 ~ 24 degrees (Angle); 3, qualified – 30 ~ 30 degrees (Angle). Accounting, every 6 degrees as a case, that is to say, the most minute hand coordination within no more than five points. When assembling the minute hand of installation error, the main reason is the difference in produce the minute hand coordination. , poor points coordinate inspection method in industry standard is such regulations: “will be the same with” 3 “, “6”, “9”, “12” centre, check the minute hand Angle deviation from the center of the “12” operator “, should meet the above requirements, the check belongs to use reliability of a watch.
Interestingly, in the execution of ordinary mechanical watches before industry standard QB/T1249-1991, when the minute hand poor coordination is such regulations: “when the minute hand and the 12 operator overlap, clockwise the angular displacement of the deviation when the operator should be less than 3 degrees”.
Accounting, most minute hand coordination within no more than 6 points, apparently now implement the standards is the provisions of the strict than before. It is said that early in the planned economy time, watch people in the industry and business in the discussion of this standard, each other opinions are not unified, business people can not accept six minutes of the coordination of the needle is poor, finally, became an minute hand on the “12”, while the angular displacement of the clockwise deviation when the operator should be less than 3 degrees. Actual inside and outside in the same, no more than figures show little.
The problem about the minute hand coordination, there is another reason, that is the problem of gear backlash, in clockwise and counterclockwise dial needle, you can tell the difference between to, there is always a direction is larger, relatively small in the other direction. To import watches, ROLEX when the minute hand coordination difference is very small, also including its calendar jumps error, give a person with deep impression, this is related to manufacturing precision and assembly quality. By the way, for the second hand of counterpoint, are no provisions in the relevant standards of the clock. Because, from the structure and machining accuracy of watches, both quartz and mechanical watches, is impossible to guarantee its in a circle in each position, the second hand on the scale.