Hardinge has taught the use of left-hand turning tools for heavy cuts on slant bed turning centers. By running “reverse spindle” (M4 direction), the left-hand stick tooling allows the cutting forces to be directed toward the bed of the machine. This allows the operator the advantage to push tools harder, reducing chatter and offering better tool life.
Machine tools that run “forward spindle” use right-hand tooling (M3 direction) in upside down position. This condition tends to lift the top plate upward and away from the machine bed. This is absolutely a less stiff scenario and can cause numerous problems.
Another big advantage to left-hand tooling is that the operator can see the insert and can easily check it for wear (rather than upside down tooling where the insert is hidden from view).
