"Single-column vertical lathe front and back tool judgment criteria" is a concept in the field of machining that is used to determine when to use the front and back sides of a cutting tool on a single-column vertical lathe.
On a single-column vertical lathe, the front and back sides of the cutting tool are typically used for different types of cutting operations, such as roughing and finishing. The following are general criteria for judging the front and back of a knife:

1. Front cutter: Front cutter is usually used for fine machining operations. It has a smaller edge angle, usually zero or a positive number, allowing it to cut smaller chips and obtain a higher surface quality. Front cutting tools are commonly used for finishing, face milling and turning detailed features.
2. Back Tools: Back Tools are typically used for roughing operations. It has a larger edge angle, usually negative, to remove large amounts of material faster. Counter-facing tools are typically used for tasks such as roughing, quick material removal, rough turning, and more.

In actual operation, judging when to use front and back tools usually depends on the requirements of the machining task, the material of the workpiece, and the cutting parameters. Operators need to select the appropriate tools based on these factors and ensure they are installed correctly on the machine tool to obtain the desired machining results.
In summary, the selection criteria for single-column vertical lathe front and back tools involve factors such as cutting tasks, tool edge angles, and workpiece requirements to ensure efficient, precise, and good-quality machining.