Recommended Cutting Speeds For HSS End Mills

Mill Speed is measured by the rate at which the outside diameter of the tool moves in relation to the work piece. This speed is known as Surface Feet Per Minute (SFM) and is shown in the table below. The formula used to convert SFM to Revolutions Per Minute (RPM) is:

RPM = 3.82 X          SFM         
  Mill Diam (Inch)

The speeds shown in this table are a generalization and it is recommended that the user start at the lower end of the range and build up to the maximum after trial indicates this is possible.

Fractional Size

Material
Hardness BHN
Speed SFM
Speed RPM
Steel
Magnetic Soft
<120
92-130
Structural
<200
72-105
Plain Carbon
<250
60-82
Alloyed
<250
60-82
Alloyed (Hardened & Tempered)
250-350
45-65
Alloyed (Hardened & Tempered)
>350
22-40
Stainless Steel
Free Machining
<250
60-82
Austenitic
<250
45-65
Ferritic Austenitic
<300
22-40
Cast Iron
Lamellar Graphite
<150
72-105
Lamellar Graphite
150-300
60-82
Nodular Graphite (Malleable)
<200
72-105
Nodular Graphite (Malleable)
200-300
45-65
Titanium
Unalloyed
<200
72-105
Alloyed
<270
45-65
Alloyed
270-350
22-40
Nickel
Unalloyed
<150
92-130
Alloyed
>270
22-40
Alloyed
270-350
22-32
Copper
Unalloyed
<100
195-260
Brass - Bronze
<200
92-130
Brass
<200
115-165
Bronze High Strength
<470
32-50
Aluminum - Magnesium
Unalloyed
<100
260-330
Silicon Alloyed < 5%
<150
195-260
Silicon Alloyed > 5 < 10%
<120
130-195
Silicon Alloyed > 10%
<120
115-165
Plastic
Thermoplastic
-
195-260
Thermosetting
-
130-195

Recommended Feeds For Milling

Mill Diameter
Slot Drill - Feed per tooth
End Mill - Feed ber tooth
1/16 - 3/32
1/8 - 5/32
3/16 - 7/32
1/4 - 7/16
1/2 - 1"
Over 1"
0.0005
0.0007
0.0010
0.0020
0.0030
0.0050
0.0005 - 0.0010
0.0007 - 0.0012
0.0010 - 0.0015
0.0015 - 0.0020
0.0020 - 0.0025
0.0025 - 0.0030

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