groove mark的意思|示意

However, the sectional profile of groove and rake Angle are frequently prone to be below the mark even being rejected because of a large spiral Angle.

但若所加工的螺旋角较大，则易出现槽形和前角不符要求，乃至报废。

A closer inspection of the tool mark shows a series of parallel teeth marks, probably from the use of a plumber's wrench or tongue-and-groove pliers.

放大后的检验，可见一系列平行的齿纹，有可能来自管钳，会其他靠钳齿来抓牢工件并旋转的钳子。