A tool quick-stop device for a lathe has a base, bottom plate, front side plate, rear side plate, right side plate, left side plate, top fixed plate, tool bar, cam lever, buffer spring, cylindrical guide rail, adjusting nut, first locking nut, double end stud, second locking nut, pressure spring, pressing plate, hold-down bolt and pin shaft. The cam lever supports the tool bar before tool falling. When tool falling is required, the cam lever is rotated through external force. When the cam lever rotates over a certain position, the tool bar instantaneously loses supporting force. Under strong pressure of the pressure spring, the tool bar falls the tool with great acceleration and is separated from the cutting region in a short period of time and the cutting root is frozen.

A tool quick-stop device for a lathe has a base, bottom plate, front side plate, rear side plate, right side plate, left side plate, top fixed plate, tool bar, cam lever, buffer spring, cylindrical guide rail, adjusting nut, first locking nut, double end stud, second locking nut, pressure spring, pressing plate, hold-down bolt and pin shaft. The cam lever supports the tool bar before tool falling. When tool falling is required, the cam lever is rotated through external force. When the cam lever rotates over a certain position, the tool bar instantaneously loses supporting force. Under strong pressure of the pressure spring, the tool bar falls the tool with great acceleration and is separated from the cutting region in a short period of time and the cutting root is frozen.

Cutting tools and tool holders for pipe cutting frames are disclosed. Example cutting tools include a tool holder and a cutting insert removably securable in the tool holder. Example cutting inserts include: first and second side surfaces; first and second locating surfaces configured to locate the cutting insert in the tool holder between corresponding first and second clamping surfaces of the tool holder, wherein the first locating surface protrudes from the cutting insert with angled locating surfaces extending from the first locating surface to the first and second side surfaces, and the second locating surface comprising an indentation; front end and rear end surfaces; a rake surface, the rake surface and the front end surface forming a cutting edge; and an insert stop surface at a rear of the rake surface, extending from the rake surface to the first locating surface and the angled locating surfaces.