Circumferential Speeds for High Speed Twist Drills
Cutting Speed
Ft./min. M./min.
Ferrous Materials
Non Alloy Steels
(a) Upto 0.40% Carbon Content 80-100 24-30
(b) 0.40% to 0.70% Carbon Content 60-80 18-24
(c) Over 0.70% Carbon Content 40-60 12-18
Alloy Steels    
(a) Upto 60 tons Tensile 50-70 15-21
(b) 60-80 tons Tensile 30-50 9-15
(c) Over 80 tons Tensile 15-30 4.5-9
Austenitic Stainless Steels    
Non Magnetic    
Magnetic Stainless    
Steel Magnetic 40-60 12-18
Alloyed Cast Iron 50-70 15-21
Grey Cast Iron 80-100 24-30
12-14% Manganese Steels 12-14 3.5-4.5
Non Ferrous Materials    
Bronze Ordinary 100-200 30-60
Brass 200-250 60-75
Copper 65-70 19-21
Magnesium & Magnesium 200-300 60-90
Alloys    
Monel Metal 20-50 6-15
Nimonic Alloys 20-30 6-9
Nickel 30-50 9-15
Zinc base Alloys(mazac) 150-250 45-75