The machining of a corner with a radius or a chamfer larger than the radius of the insert always requires the combination of movement in two directions. Problems, such as insert breakage, result when this combined operation is used while the insert is plunged into the workpiece with material on all sides. Insert breakage is caused by forces acting simultaneously in two different directions (F1 and F2 as shown).



Recommended procedure to optimize machining and eliminate insert breakage
1 Groove to the required depth.
2 Pull the insert back from the workpiece. This eliminates side forces acting on the insert.
3 Move the insert to the position required to start machining the radius or chamfer.
4 Proceed to cut the radius or chamfer.
5 Longitudinal turning can then begin.


Note: If the final dimensions were reached in cutting the radius or chamfer, the deflection compensation factor Δ/2 should be used prior to beginning the longitudinal turning.