VAR-A-TECH - Series 157 Series 157 VAR-A-TECH Vibration Reducing End Mill with Ball End. View Speeds and Feeds page. Features: Reduces Chatter & Vibration Allows for Roughing and Finishing at the same time. Allows for aggressive machining with greater depths-of-cuts and heavier feeds Great for Titanium, High Temperature Alloys, Steels, Stainless Steels, High Strength Alloys and Cast Iron Standard with Advanced AlTiN Coating (Part Number ends in 4) Standard with Advanced nACRo® Coating (Part Number ends in 5)