The following information is a general guide. Specific jobs may need to be modified because of varying job conditions, such as coolant, equipment and job requirements. Guide for Peripheral Speeds General Guide for Cutting Speeds and Feeds for Drills Drill feeds are governed by the size of the drill and also the material to be drilled. The lower feeds should be used when drilling relatively hard materials such as alloy steels. The higher feeds should be used when drilling relatively soft materials such as aluminum and brass. These feeds are based on the peripheral speed of a drill. Guide for Drill Feeds Drill Dia. Feed per Rev. Drill Dia. Feed per Rev. Under 1/80 .0010 - .0020 Under 3mm .025 - .05mm 1/80 - 1/40 .0020 - .0040 3 - 6mm .05 - .100mm 1/40 - 1/20 .0040 - .0070 6 - 13mm .100 - .180mm 1/20 - 10 .0070 - .0150 13 - 25mm .180 - .370mm Over 10 .0150 - .0250 Over 25mm .370 - .630mm Material Feet/Minute Meters/Minute Carbon Drill HSS Drill Carbon Drill HSS Drill Machinery Steel 30 80 9 24 Cast Iron 35 100 10.5 30 Brass 60 200 18 60 Alloy Steel – 50 – 15 Drill Diameter Peripheral Speeds – Feet per Minute (Meters per Minute) Revolutions per Minute in mm 30 (9 ) 50 (15) 60 (18) 80 (24) 100 (30) 200 (60) 1/8 3 917 1528 1833 2445 3056 6112 1/4 6 458 764 917 1222 1528 3056 1/2 13 229 382 458 611 764 1528 1 25 115 191 229 306 382 764 1-1/2 38 76 127 153 204 255 509 2 50 57 96 115 153 191 382 3 75 38 64 76 102 127 255 589 starrett.com R eference T ables