The most important aspect of milling with end mills is to run the tool at the proper RPM (revolutions per minute or spindle speed) and IPM (inches per minute or feed rate). We have broken these recommendations down into material categories so you can make better decisions with how to productively run your end mills. Certain high performance mills have very specific running parameters relative to their material families. We have listed these also as individual recommendations by coating family. These documents are downloadable in pdf formats by clicking the links below.
When choosing the right cutting parameters to run, most people focus on the speed which relates to the machine RPM. This is a mistake! Focus on on the proper feed per tooth (FPT) first, and then adjust the speed. Often when a part is programmed, and is being proven out for production, the programmer will choose conservative parameters and encounter chatter. Chatter is nothing more that part vibration or noise, because the tool is not cutting properly. Usually, the first response is to slow the RPM and the chatter will go away. This often works, but this is unproductive. What has just happened is that by reducing the speed and keeping the feed constant, the FPT has increased. And most likely the FPT before was too low in the first place and that was what caused the chatter.
The speeds and feeds formulas are in the bottom of the charts below. If you follow these guidelines, you will have a much greater success rate in part programming, and you will be milling more efficiently.
Note: These cutting feeds and speeds charts work with Accupro, Niagara, Data Flute, SPETool and all end mill brands. We will have all of Harvey Tool speeds and feed charts loaded soon.
We have created an excellent speeds and feeds calculator which incorporates these charts into the calculations. It generates ranges of SFM or SMM and allows you to decide what SFM is appropriate. It then automatically calculates the RPM. Then it gives you a range for FPT and allows you to decide what is appropriate. Then it automatically calculates the IPM or millimeters per minute (MMPM). Try it out! It is easy to understand.
Stainless Steels Speeds and Feeds
SMM = SFM X .3048 |
Speeds |
Feeds - IPT (inches/tooth) and MMPT (mm/tooth) |
|||||||||
Material Group |
Examples |
SFM |
1/8" 3mm |
3/16" 5mm |
1/4" 6mm |
5/16" 8mm |
3/8" 10mm |
1/2" 12mm |
5/8" 16mm |
3/4" 20mm |
1" 25mm |
Steels P |
Mild - 1018 (.2-.3 Carbon) |
500 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Mild - 4140 (.4-.5 Carbon) |
350 |
||||||||||
Tool Steels A2/D2/H13/P20 |
280 |
.0004" .010mm |
.0009" .023mm |
.0013" .033mm |
.0016" .041mm |
.0019" .048mm |
.0021" .053mm |
.0026" .066mm |
.0028" .071mm |
.0028" .071mm |
|
Forgings |
180 |
||||||||||
Cast Irons K |
Soft |
600 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Medium |
400 |
||||||||||
Hard Chilled |
350 |
||||||||||
300 |
|||||||||||
Stainless Steels M |
Free Machining |
350 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Ferritic |
280 |
||||||||||
Austenitic 304/316 |
250 |
.0004" .010mm |
.0009" .023mm |
.0013" .033mm |
.0016" .041mm |
.0019" .048mm |
.0021" .053mm |
.0026" .066mm |
.0028" .071mm |
.0028" .071mm |
|
Martensitic |
210 |
||||||||||
PH 17-4 PH |
160 |
||||||||||
Special Alloys S |
Titanium 6AL-V4 |
240 |
.0003" .008mm |
.0005" .013mm |
.0007" .018mm |
.001" .025mm |
.0012" .030mm |
.0014" .036mm |
.0017" .043mm |
.0019" .048mm |
.0025" .063mm |
Co-Based Alloys Stellite |
140 |
.0004" .010mm |
.001" .025mm |
.0012" .030mm |
.0015" .038mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.003" .076mm |
.003" .076mm |
|
Ni-Based Alloys Inconel 625/718 |
140 |
||||||||||
Fe-Based Alloys Incoloy 800-802 |
160 |
||||||||||
Hardened Steels H |
35-45Rc |
270 |
.0004" .010mm |
.001" .025mm |
.0012" .030mm |
.0015" .038mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.003" .076mm |
.003" .076mm |
45-55Rc |
200 |
||||||||||
70 |
|||||||||||
Speeds and Feeds Formulas |
|||||||||||
Speeds - Inch SFM = surface feet per minute RPM = SFM X 3.82 / Tool Diameter |
Speeds - Metric SMM = surface meters per minute RPM = SMM X 318.06 / Tool Diameter |
||||||||||
Radial Depth of Cut in Percentage of Diameter |
50% |
30% |
20% |
15% |
10% |
5% |
1% |
||||
CLF = chip load factor |
1.0 |
1.1 |
1.2 |
1.4 |
1.8 |
2.3 |
5.0 |
||||
Feeds - Inch IPM = inches per minute IPT = inches / tooth IPM = RPM X number of teeth X CLF X IPT |
|
Feeds - Metric MMPM = mm per minute MMPT = mm / tooth MMPM = RPM X number of teeth X CLF X MMPT |
SMM = SFM X .3048 |
Speeds |
Feeds - IPT (inches/tooth) and MMPT (mm/tooth) |
|||||||||
Material Group |
Examples |
SFM |
1/8" 3mm |
3/16" 5mm |
1/4" 6mm |
5/16" 8mm |
3/8" 10mm |
1/2" 12mm |
5/8" 16mm |
3/4" 20mm |
1" 25mm |
Steels P |
Mild - 1018 (.2-.3 Carbon) |
420 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Mild - 4140 (.4-.5 Carbon) |
300 |
||||||||||
Tool Steels A2/D2/H13/P20 |
240 |
.0004" .010mm |
.0009" .023mm |
.0013" .033mm |
.0016" .041mm |
.0019" .048mm |
.0021" .053mm |
.0026" .066mm |
.0028" .071mm |
.0028" .071mm |
|
Forgings |
150 |
||||||||||
Cast Irons K |
Soft |
540 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Medium |
360 |
||||||||||
Hard Chilled |
300 |
||||||||||
Malleable |
270 |
||||||||||
Stainless Steels M |
Free Machining |
360 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Ferritic |
240 |
||||||||||
Austenitic 304/316 |
220 |
.0004" .010mm |
.0009" .023mm |
.0013" .033mm |
.0016" .041mm |
.0019" .048mm |
.0021" .053mm |
.0026" .066mm |
.0028" .071mm |
.0028" .071mm |
|
Martensitic |
180 |
||||||||||
PH 17-4 PH |
150 |
||||||||||
Special Alloys S |
Titanium 6AL-V4 |
210 |
.0003" .008mm |
.0005" .013mm |
.0007" .018mm |
.001" .025mm |
.0012" .030mm |
.0014" .036mm |
.0017" .043mm |
.0019" .048mm |
.0025" .063mm |
Co-Based Alloys Stellite |
120 |
.0004" .010mm |
.001" .025mm |
.0012" .030mm |
.0015" .038mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.003" .076mm |
.003" .076mm |
|
Ni-Based Alloys Inconel 625/718 |
120 |
||||||||||
Fe-Based Alloys Incoloy 800-802 |
150 |
||||||||||
Hardened Steels H |
35-45Rc |
240 |
.0004" .010mm |
.001" .025mm |
.0012" .030mm |
.0015" .038mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.003" .076mm |
.003" .076mm |
45-55Rc |
180 |
||||||||||
55-65Rc |
60 |
||||||||||
Speeds and Feeds Formulas |
|||||||||||
Speeds - Inch SFM = surface feet per minute RPM = SFM X 3.82 / Tool Diameter |
Speeds - Metric SMM = surface meters per minute RPM = SMM X 318.06 / Tool Diameter |
||||||||||
Radial Depth of Cut in Percentage of Diameter |
50% |
30% |
20% |
15% |
10% |
5% |
1% |
||||
CLF = chip load factor |
1.0 |
1.1 |
1.2 |
1.4 |
1.8 |
2.3 |
5.0 |
||||
Feeds - Inch IPM = inches per minute IPT = inches / tooth IPM = RPM X number of teeth X CLF X IPT |
|
Feeds - Metric MMPM = mm per minute MMPT = mm / tooth MMPM = RPM X number of teeth X CLF X MMPT |
SMM = SFM X .3048 |
Speeds |
Feeds - IPT (inches/tooth) and MMPT (mm/tooth) |
|||||||||
Material Group |
Examples |
SFM |
1/8" 3mm |
3/16" 5mm |
1/4" 6mm |
5/16" 8mm |
3/8" 10mm |
1/2" 12mm |
5/8" 16mm |
3/4" 20mm |
1" 25mm |
Steels P |
Mild - 1018 (.2-.3 Carbon) |
350 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Mild - 4140 (.4-.5 Carbon) |
250 |
||||||||||
Tool Steels A2/D2/H13/P20 |
200 |
.0004" .010mm |
.0009" .023mm |
.0013" .033mm |
.0016" .041mm |
.0019" .048mm |
.0021" .053mm |
.0026" .066mm |
.0028" .071mm |
.0028" .071mm |
|
Forgings |
125 |
||||||||||
Cast Irons K |
Soft |
450 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Medium |
300 |
||||||||||
Hard Chilled |
250 |
||||||||||
Malleable |
225 |
||||||||||
Stainless Steels M |
Free Machining |
300 |
.0006" .016mm |
.0011" .028mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.0028" .071mm |
.0032" .081mm |
.0033" .084mm |
.0041" .104mm |
Ferritic |
200 |
||||||||||
Austenitic 304/316 |
180 |
.0004" .010mm |
.0009" .023mm |
.0013" .033mm |
.0016" .041mm |
.0019" .048mm |
.0021" .053mm |
.0026" .066mm |
.0028" .071mm |
.0028" .071mm |
|
Martensitic |
150 |
||||||||||
PH 17-4 PH |
125 |
||||||||||
Special Alloys S |
Titanium 6AL-V4 |
175 |
.0003" .008mm |
.0005" .013mm |
.0007" .018mm |
.001" .025mm |
.0012" .030mm |
.0014" .036mm |
.0017" .043mm |
.0019" .048mm |
.0025" .063mm |
Co-Based Alloys Stellite |
100 |
.0004" .010mm |
.001" .025mm |
.0012" .030mm |
.0015" .038mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.003" .076mm |
.003" .076mm |
|
Ni-Based Alloys Inconel 625/718 |
100 |
||||||||||
Fe-Based Alloys Incoloy 800-802 |
125 |
||||||||||
Hardened Steels H |
35-45Rc |
200 |
.0004" .010mm |
.001" .025mm |
.0012" .030mm |
.0015" .038mm |
.0017" .043mm |
.002" .051mm |
.0025" .064mm |
.003" .076mm |
.003" .076mm |
45-55Rc |
150 |
||||||||||
50 |
|||||||||||
Non- Ferrous N |
Al/Al Alloys |
500 |
.0011" .028mm |
.0017" .043mm |
.0022" .056mm |
.0027" .068mm |
.0032" .081mm |
.0042" .107mm |
.0065" .165mm |
.0085" .216mm |
.0092" .234mm |
Brass/Bronze |
400 |
||||||||||
Mg/Mg Alloys |
700 |
||||||||||
Plastics/Bakelite |
800 |
||||||||||
Speeds and Feeds Formulas |
|||||||||||
Speeds - Inch SFM = surface feet per minute RPM = SFM X 3.82 / Tool Diameter |
Speeds - Metric SMM = surface meters per minute RPM = SMM X 318.06 / Tool Diameter |
||||||||||
Radial Depth of Cut in Percentage of Diameter |
50% |
30% |
20% |
15% |
10% |
5% |
1% |
||||
CLF = chip load factor |
1.0 |
1.1 |
1.2 |
1.4 |
1.8 |
2.3 |
5.0 |
||||
Feeds - Inch IPM = inches per minute IPT = inches / tooth IPM = RPM X number of teeth X CLF X IPT |
|
Feeds - Metric MMPM = mm per minute MMPT = mm / tooth MMPM = RPM X number of teeth X CLF X MMPT |
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