Ball Nose Reference & Technical Information

Application Information

Technical Considerations

Recommendations

Ball Nose Feed, Speed and Diameter Compensation

Table 1: Effective Cutting Diameter (ECD)

Depth of Cut
Insert Diameter   .005 .010 .015 .025 .035 .050 .100 .125 .150 .200 .250
.250 .070 .098 .119 .150 .173 .200 .245 .250      
.375 .086 .121 .147 .187 .218 .255 .332 .354 .367 .374  
.500 .099 .140 .171 .218 .255 .300 .400 .433 .458 .490 .500
.625 .111 .157 .191 .245 .287 .339 .458 .500 .534 .583 .612
.750 .122 .172 .210 .269 .316 .374 .510 .559 .600 .663 .707
1.000 .141 .199 .243 .312 .368 .436 .600 .661 .714 .800 .866
1.250 .158 .223 .272 .350 .412 .490 .678 .750 .812 .917 1.000

Figure 1

  1. Select diameter of tool to be used.
  2. Determine Depth of Cut (DOC) to be used.
  3. Refer to Figure 1 and Table 1 to find the Effective Cutting Diameter (ECD).
  4. Refer to Feed and Speed chart below to select the surface footage to be used (SFM).
  5. Calculate RPM using the ECD and Vc. (Vc x 318.5 / ECD = RPM)
  6. Refer to Table 2 to determine Feed Rate Adjustment (FRA).
  7. Refer to chart below to select Feed per Tooth (FPT). Calculate Inches per Minute (IPM). (RPM x FPT x FRA = IPM)

Table 2: Feed Rate Adjustment (FRA)

Insert Diameter
Depth of Cut   1/4" 5/16" 3/8" 1/2" 5/8" 3/4" 1" 1-1/4"
.005 3.6 4.0 4.4 5.0 5.6 6.1 7.1 7.9
.010 2.6 2.8 3.1 3.6 4.0 4.4 5.0 5.6
.015 2.1 2.3 2.6 2.9 3.3 3.6 4.1 4.6
.020 1.8 2.0 2.2 2.6 2.8 3.1 3.6 4.0
.025 1.7 1.8 2.0 2.3 2.6 2.8 3.2 3.6
.050 1.2 1.4 1.5 1.7 1.8 2.0 2.3 2.6
.075 1.1 1.2 1.2 1.4 1.5 1.7 1.9 2.1
.100   1.1 1.1 1.2 1.4 1.5 1.7 1.8
.125     1.1 1.2 1.3 1.3 1.5 1.7
.150       1.1 1.2 1.3 1.4 1.5
.175         1.1 1.2 1.3 1.4
.200           1.1 1.3 1.4
.250             1.2 1.2
.300             1.1 1.2
.400               1.1

Use multiple above to calculate adjusted feed rate.

Recommended Cutting Speeds & Feeds for Ball Nose Finishing Mills

Ball Nose Recommended Cutting Speeds

Click here or on the chart above for a larger version (opens in a new window).

This chart is also part of our Ball Nose catalog PDF.

Ball Nose Troubleshooting

Troubleshooting
Concern Possible Cause Solutions
Insert wear at tip
  • Not enough chip load
  • Verify correct speed and feed
  • Increase feed rate
  • Decrease RPM
  • Increase DOC
Insert wear appears high (flank wear)
  • Not enough chip load
  • Surface footage is high
  • Incorrect grade or coating
  • Verify correct speed and feed
  • Increase feed rate
  • Decrease RPM
  • Consider different insert
Insert Chipping
  • Surface footage is low
  • Incorrect grade or coating
  • Using CB style insert incorrectly
  • Feed too high
  • Verify correct speed and feed
  • Increase spindle speed
  • Decrease feed rate
  • Change insert selection
  • Decrease DOC
  • Use N style insert
Built-up edge on insert
  • Low surface footage
  • Light chip load (feed per tooth)
  • Incorrect coating
  • Verify correct speed and feed
  • Increase cutting speed
  • Increase feed rate
  • Select different coating
Poor finish/chatter
  • Cutter hung out too far
  • Excessive runout
  • Use Carbide Core cutter body
  • Reduce tool gage length
  • Check tool holder wear
Tool shank breaks
  • Tool pressure too great
  • Fatigued cutter body
  • Decrease DOC
  • Reduce tool gage length
  • Decrease feed rate

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