在钻探管材螺纹中，有不少是浅牙、梯形螺纹。多年来，对于这类螺纹，其牙宽尺寸的标注，究竟在牙顶宽上，还是在牙底宽上？对此各家颇有争议。反映在各国、各公司的标准和图纸上，也有不同的标法。另外，对牙顶宽（或牙底宽）公差，牙高公差，螺纹的大、小径公差，牙形角公差间的关系及其在检测 In drilling pipe thread, there are many shallow teeth, trapezoidal thread. Over the years, for this type of thread, the size of the tooth width dimension, whether in the top of the tooth width, or in the bottom width? This is quite controversial. Reflected in the standards of all countries and companies and drawings, there are different standards. In addition, the tooth top width (or bottom width) tolerance, tooth height tolerance, the thread of the large, small diameter tolerances, the relationship between tooth profile angle tolerance and its detection