Adjusting for Stepped Cutting

Stepped cutting is utilized when heavy depth of cut is required. The inserts are set at different diameters. The insert cutting the smaller diameter is given axial lead 1.25 times greater than the feed per revolution over the other insert. Use only insert holders with 0° lead. Stepped cutting allows 1.75 x the depth of cut per tables on page 144. Feed rates must be reduced to .5 x appropriate value.

Rules of Stepped Cutting:

• Use insert holders with 0° lead.
• Set height in inner cutting edge to provide lead 1.25 times greater than the feed per revolution.
• Feed rate as roughing with a single cutter.
• Remove half of the material to be removed with each insert. This should be sufficient for most applications.
  
  

To balance cutting forces, use the formula below:

A1 – Hole starting diameter
A2 – Inside cutter set diameter
A3 – Outside cutter set diameter

Adjusting for Stepped Cutting:

Stepped cutting allows removal of more metal since each insert is set at a different diameter.

• Make sure the height cam is located with the reference mark in the vertical position as shown.
• Loosen the insert holder clamps. Re-tighten enough to put drag on the insert holder.
• Adjust the diameter by turning the adjusting screw. Always adjust in the clockwise direction. Set the diameter of each insert to remove approximately one half the material.
• Using the cam screw, adjust the inner cutting edge so that it has a lead over the outer cutting edge. This lead should be a minimum of 11/2 times the feed per revolution.
• Tighten the insert holder clamps.

NOTE: When using stepped cutting, the feed rate must be that of a single cutter.