车削左旋螺纹时，情况正好相反。<ref>[https://www.doc88.com/p-746868815814.html 螺纹升角对车刀角度的影响],道客巴巴</ref>

[[File:来完成对.jpg|缩略图|300px|[https://image.baidu.com/search/detail?ct=503316480&z=undefined&tn=baiduimagedetail&ipn=d&word=螺纹车刀&step_word=&ie=utf-8&in=&cl=2&lm=-1&st=undefined&hd=undefined&latest=undefined&copyright=undefined&cs=26242703,765800806&os=732031658,1849162582&simid=3334824561,458009593&pn=44&rn=1&di=98010&ln=944&fr=&fmq=1581246360681_R&fm=&ic=undefined&s=undefined&se=&sme=&tab=0&width=undefined&height=undefined&face=undefined&is=0,0&istype=0&ist=&jit=&bdtype=0&spn=0&pi=0&gsm=0&objurl=http%3A%2F%2Fyzhtml01.book118.com%2F2016%2F09%2F21%2F22%2F28530501%2F32.files%2Ffile0001.png&rpstart=0&rpnum=0&adpicid=0&force=undefined&ctd=1581246394514^3_1007X610%1 原圖鏈接][https://max.book118.com/html/2015/1104/28530501.shtm 来自原创立文档]]]

=-1^。）30'~0^。30'

==螺纹升角ψ对螺纹车刀工作前角的影响==

[[File:·来完成的.jpg|缩略图|300px|[https://www.wendangwang.com/doc/caec96abb6ebb3bc93e8d6cf/5 来自文档网]]]