Machining Speeds and Feeds Amarillo CollegeMachining Speeds and Feeds Material Speed Factor SFPM SURFACE FEET / MIN Hi Speed Steel Carbide = 2 4 X Hi Speed Steel A Stainless Steel = 35 SFPM take a cut / minB Tool Steel = 50 SFPM includes 4140 C Cast Iron = 75 SFPM get below scale no lubricant D Mild Steel = 100 SFPM