Effect of the helix on the stability diagram: Left) Variation of the |g| funtion with the axial depth of cut for j=1. Right) Unstable islands. Simulation made for a tool with a diameter of 16 mm, helix angle of 73º, 2 cutting edges , Kt=800 N/mm2 , Kr =100 N/mm2 , Ka =200 N/mm2 , ae =2 mm in down-milling.