I've noticed a few comments about cutting speeds here and thought an extract from a reference book I have might be of interest to those who don't have access to one;

Material suggested - speed ft/min

  • Annealed, High Speed & Stainless Steel - 50
  • Annealed Carbon Steel - 60
  • Cast Iron, Mild Steel, Wrought Iron - 80
  • Brass - 200
  • Aluminium & alloys - 300


The RPM required can be calculated by the formula:
Cutting Speed / Quarter of diameter = RPM

Eg. Mild Steel bar 8" in diameter
80 / 2 = 40 RPM

Of course, the bigger it is the slower the revs.