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drilling systems from sterling gun drills





Speed & Feed Charts

Gun Drill, Half Round Drill, TWINMASTERTWINMASTER® - Registered Trademark of Sterling Gun Drills Twin Flute Drill

RPM=SFM ÷ 0.262 ÷ DRILL DIA.



The assumption is made that proper bushing or pilot hole size, oil or coolant type and pressure, and general machine condition is acceptable. The information below is a starting reference only!

High Pressure (Hi Press.) refers to a gun drill machine or the equivalent pressure. Spraymist (S/mist) refers to our DM2000 / DM3000 kits, or high "EP" coolant at no less than one third gun drill machine pressure for the diameter.

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TOOL STEELS
D,S,M,O,H,P Series Hi Press S/Mist
Rc SFM SFM
17-22 250 160
22-27 200 130
27-32 150 100
32-37 100 70
 
ALLOY STEELS
4000, 5000, 8000 Series Hi Press S/Mist
Rc SFM SFM
17-22 280 190
22-27 230 160
27-32 180 130
32-37 130 100
37-42 80 70
 
Low to Med. CARBON STEEL
C1010-1550
Rc SFM SFM
12-17 330 220
17-22 280 190
22-27 230 160
27-32 180 130
32-37 130 100
37-42 80 70
 
STAINLESS STEEL* 300 Series
300 Series & PH
Rc SFM SFM
12-17 230 150
17-22 200 130
22-27 170 110
27-32 140 90
32-37 110 70
37-42 80 50
Free Machining, + 30%
 
STAINLESS STEEL *  400 Series
400 Series
Rc SFM SFM
12-17 280 170
17-22 240 150
22-27 200 130
27-32 160 110
32-37 120 90
37-42 80 70
Free Machining, + 30%
 
CAST IRON
Grey
Rc SFM SFM
12-17 400 260
17-22 350 220
22-27 300 180
27-32 250 140
With Free Carbides -50%
Ni-Resist -60%
 
CAST IRON
Ductile, Nodular
Rc SFM SFM
12-17 300 200
17-22 250 170
22-27 200 140
27-32 150 110
32-37 100 80
Ductile, Ni-Resist -50%
 
TITANIUM*
6A1 4V, Some Others
Rc SFM SFM
12-17 260 150
17-22 220 130
22-27 180 110
27-32 140 90
32-37 100 70
37-42 60 50
 
HIGH TEMP. ALLOYS*
Nickel Based Hi Press S/Mist
Rc SFM SFM
12-22 120 80
22-32 90 60
32-42 60 40
Cobalt Base -40%
Iron Base +20%
 
COPPER ALLOYS*
Berryllium, Ni-Based Hi Press S/Mist
Rc SFM SFM
12-22 200 130
22-32 130 90
32-37 60 50
 
SOFT ALLOYS Non Ferrous
Aluminum, Copper, Free Brass, Magnesium 600 400 or

toolholder limit
All Conditions
 
* Consult Sterling Gun Drills to verify application requirements.

Call for Technical & Engineering Support

Approximate Feed Rate (IN./REV.)

Gun Drills on gundrilling machines, also with spraymist @ 100 + psi, or high pressure, high "EP" coolant. Half Round drills on spraymist, increase feed by 25%.
For TWINMASTER® Twin Flute drills, high pressure or spraymist, increase feed by 50 - 100%.

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Dia.
(inch)		 Steels
Low, Med.
Carbon		 Steels,
Alloy,
Tool,
416 S.S.		 Stainless*
300 Ser,
Titanium,
High Temp.
Ni Alloys		 Cast Iron,
Grey,
Alum.,
Free cut.		 Cast Iron,
Ductile,
Nodular		 Non-Ferrous
Alloys, Difficult
To Chip
.125"** .00015" .00015" .0001" .00015" .00015" .0001"
.187"** .0003" .0003" .0002" .0003" .0003" .0002"
.250" .00045" .00045" .0003" .0005" .0005" .0003"
.375" .0007" .0006" .0005" .0013" .001" .0005"
.500" .0008" .0007" .0006" .002" .0015" .0007"
.625" .001" .0009" .0007" .0025" .002" .0009"
.750" .0013" .0011" .0008" .003" .0025" .0011"
1.00" .0018" .0015" .001" .004" .003" .0015"
*Consult Sterling Gun Drills to verify application requirements.
** N/A Half Round drill. Below minimum manufacturing diameter.
Drill lengths over 30:1, reduce feed rate by 20%.





Oil Pressure, GPM, Unsupported Drill Length

Gun Drill Machine
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Diameter
(inches) 		Oil Pressure
(PSI) 		GPM Max. Unsupported Length
(per spindle) High SFM Low SFM
Single
Flute 		Twin
Flute 		(inches)
.125" 1500 1.0 N/A 3" 6"
.187" 1150 1.8 N/A 6" 12"
.250" 925 2.3 3.0 8" 16"
.375" 675 4.5 6.0 12" 24"
.500" 525 7.0 7.5 16" 32"
.625" 450 9.0 9.0 20" 40"
.750" 400 11.5 11.0 24" 48"
1.000" 250 17.0 14.0 32" 64"