四线等分左螺纹规和单线左螺纹规是一种专用量具,它的螺纹形式与常见螺纹不同,它不是普通的螺旋角形面,而是一种螺旋R形面,加上零件螺纹升角很大,超出正常的加工范围和仪器的检测范围。以前的做法是将工件装上专用夹具来计量零件的R和螺距尺寸,在万能工具显微镜上用影像法计量所需值,这种方法误差值较大。 Four-line bisector Left-hand thread gauge and single-thread left-hand thread gauge is a special measuring tool whose thread form is different from common threads. It is not an ordinary helix, but a helical R-profile, Large, beyond the normal processing range and the scope of the instrument. The previous approach is to load the workpiece with a dedicated fixture to measure the parts of the R and pitch size, the omnipotent tool microscope using the image method to measure the desired value, this method a larger error value.