车削普通螺纹及牙型截面不大的梯形螺纹或蜗杆时,为了改善切削条件,根据工件材料不同,螺纹车刀通常都磨出一定的径向正前角γ。有径向前角的螺纹车刀,因刀刃并不通过工件的轴心线,因此,被切螺纹的牙形(轴向剖面)不再是直线形,而是曲线。这种误差对一般要求不高的螺纹,可以忽略不计。但对螺 Turning ordinary threads and thread trapezoidal thread or worm cross section is not large, in order to improve the cutting conditions, depending on the workpiece material, the thread turning tools are usually worn out a certain radial positive angle γ. Radial rake angle thread turning tool, because the blade does not pass the axis of the workpiece, so the thread profile (axial profile) is no longer a straight line, but the curve. This error on the general requirements of the thread is negligible. But on the screw