Sandvik Coromant Silent tools - users guide - Manual (Page 12)

12
Cutting forces and directions
Conventional set-ups will risk overloading the boring
bar and the tool post because the bar weight and the
cutting force will act in the same direction.
The result is instability and vibration tendencies
because the tool post binds to the gibs.
By adding a counterweight, the downward force through
the tool post is balanced over the gibs resulting in a
smoother machining process.