Speeds & Feeds

Speeds & Feeds

To calculate a starting point for speeds and feeds you need specific information about the tool – Largest cutting diameter of the tool & material.

Calculating Starting Point Feeds & Speeds

  • To calculate a starting point for speeds and feeds you need specific information about the tool.
  • Largest cutting diameter of the tool
  • Material
  • Start points for speeds and feeds are calculated but are only a starting figure. They are based on the surface speed and the feed rate, outlined below.

Surface Speed

Surface speed is the speed that the material moves past the cutting edge of the tool. So in boring operations the diameter is theoretically unwound. A constant RPM is applied based on a known surface speed which will give a technically established starting point.

Material Surface Speed m/min (carbide)
Steel 150
Stainless steel 100
Cast iron 250
Nodular cast iron 100
Aluminum 1000

Calculate the RPM using the following equation:

RPM = Cutting speed/π x Diameter

Feed Rate

The feed rate is the axial speed at which the boring bar is fed through the component. This feed rate will have an impact on surface finish.

Starting point feed rate for all boring operations is between 0.1 – 0.2mm per revolution.