Drilling Guide - Air Automation Engineering

Drilling GuidePrint this page
Selection Chart Suggested surface speeds for high-speed steel drills in various materials.
Material												Speed in SFM
Alloy steel (300 to 400 Brinnel)												20 to 30
Stainless steel												30 to 40
Automotive steel forgings												40 to 50
Tool steel, 1.2C												50 to 60
Steel, .4C to .5C												70 to 80
Mild machinery, .2C to .3C												80 to 110
Hard-chilled cast iron												30 to 40
Medium-hard cast iron												70 to 100
Soft cast iron												100 to 150
Malleable iron												80 to 90
Monel metal												40 to 50
High tensile-strength bronze												70 to 150
Ordinary brass and bronze												200 to 300
Aluminum and its alloys												200 to 300
Magnesium and its alloys												250 to 400
Slate, marble and stone												15 to 25
Bakelite and similar material												100 to 150
Wood												300 to 400
Note: Carbon-steel twist drills should be run at speeds of 40 to 50 percent of those given above.
Drilling Speed (rpm) = 0.75 x Free Speed (rpm)
Hole Diameter In	Surface Speed, Feet Per Minute
Hole Diameter In	30	40	50	60	70	80	90	100	110	150	300	400	500
DRILLING SPEED, RPM (OPTIMUM OPERATING SPEED – NOT CATALOGED FREE SPEED)
1/16”	1800	2400	3000	3600	4200	4900	5500	6100	6700	9000	12,000	18,000	24,000
1/8”	900	1200	1500	1800	2100	2400	2700	3000	3400	4600	6100	9200	12,000
3/16”	600	800	100	1200	1400	1600	1800	2000	2200	3100	4100	6100	8100
1/4”	450	600	750	900	1100	1200	1400	1500	1700	2300	3100	4600	6100
5/16”	350	500	600	750	850	1000	1100	1200	1300	1800	2400	3700	4900
3/8”	300	400	500	600	700	800	900	1000	1100	1500	2000	300	4000
1/2”	200	300	400	450	550	600	650	750	850	1100	1500	2300	3000

AIR AUTOMATION ENGINEERING
230 Commerce Circle South, P.O. Box 32709, Fridley, MN 55432
(763) 571-4970, (800) 231-9205, Fax (763) 571-4923
Web Site: www.airautomation.com
E-mail: aae@airautomation.com