Table 5a. Turning-Speed Adjustment Factors for Feed, Depth of Cut, and Lead Angle
Ratio of the two cutting speeds given in the tables
Depth of Cut and Lead Angle
Ratio of Chosen Feed to Optimum Feed
V avg / V opt
1 in. (25.4 mm)
0.4 in. (10.2 mm)
0.2 in. (5.1 mm)
0.1 in. (2.5 mm)
0.04 in. (1.0 mm)
1.00 1.10 1.25 1.35 1.50 1.75 2.00 15 °
45 °
15 °
45 °
15 °
45 °
15 °
45 °
15 °
45 °
Feed Factor, F f
Depth of Cut and Lead Angle Factor, F d
1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.00 1.02 1.05 1.07 1.09 1.10 1.12 0.75 0.74 1.00 1.03 1.09 1.10 1.15 1.20 1.25 0.77 1.00 1.05 1.13 1.22 1.22 1.32 1.43 0.77 1.00 1.08 1.20 1.25 1.35 1.50 1.66 0.78 1.00 1.10 1.25 1.35 1.50 1.75 2.00 0.78 1.00 1.09 1.28 1.44 1.66 2.03 2.43 0.78 1.00 1.06 1.32 1.52 1.85 2.42 3.05 0.81 1.00 1.00 1.34 1.60 2.07 2.96 4.03 0.84 1.00 0.80 1.20 1.55 2.24 3.74 5.84 0.88
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
0.79 0.80 0.81 0.82 0.82 0.82 0.84 0.85 0.89 0.91
1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.02 1.02 1.01
0.85 0.86 0.87 0.87 0.88 0.88 0.89 0.90 0.91 0.92
1.08 1.08 1.07 1.08 1.07 1.07 1.06 1.06 1.05 1.03
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
1.18 1.17 1.15 1.15 1.14 1.14 1.13 1.12 1.10 1.06
1.29 1.27 1.25 1.24 1.23 1.23 1.21 1.18 1.15 1.10
1.35 1.34 1.31 1.30 1.29 1.28 1.26 1.23 1.19
1.12 Use with Table 1 through Table 9. Not for HSS tools. Table 1 through Table 9 data, except for HSS tools, are based on depth of cut = 0.1 inch, lead angle = 15 degrees, and tool life = 15 minutes. For other depths of cut, lead angles, or feeds, use the two feed/speed pairs from the tables and calculate the ratio of desired (new) feed to optimum feed (largest of the two feeds given in the tables), and the ratio of the two cutting speeds ( V avg / V opt ). Use the value of these ratios to find the feed factor F f at the intersection of the feed ratio row and the speed ratio column in the left half of the table. The depth-of-cut factor F d is found in the same row as the feed factor in the right half of the table under the column corresponding to the depth of cut and lead angle. The adjusted cutting speed can be calculated from V = V opt 3 F f 3 F d , where V opt is the smaller ( optimum ) of the two speeds from the speed table (from the left side of the column containing the two feed/speed pairs). See the text for examples. Table 5b. Tool Life Factors for Turning with Carbides, Ceramics, Cermets, CBN, and Polycrystalline Diamond
Turning with Carbides: Workpiece < 300 BHN
Turning with Carbides: Workpiece > 300 BHN; Turning with Ceramics: Any Hardness
Turning with Mixed Ceramics: Any Workpiece Hardness
Tool Life, T (minutes)
f m
f l
f s
f m
f l
f s
f m
f l
f s
15 45 90
1.0 0.86 0.78 0.71
1.0 0.81 0.71 0.63
1.0 0.76 0.64 0.54
1.0 0.80 0.70 0.61
1.0 0.75 0.63 0.53
1.0 0.70 0.56 0.45
1.0 0.89 0.82 0.76
1.0 0.87 0.79 0.72
1.0 0.84 0.75
180 0.67 Except for HSS speed tools, speeds and feeds given in Table 1 through Table 9 are based on 15-minute tool life. To adjust speeds for another tool life, multiply the cutting speed for 15-minute tool life V 15 by the tool life factor from this table according to the following rules: for small feeds where feed ≤ 1 ∕ 2 f opt , the cutting speed for desired tool life is V T = f s 3 V 15 ; for medium feeds where 1 ∕ 2 f opt < feed < 3 ∕ 4 f opt , V T = f m 3 V 15 ; and for larger feeds where 3 ∕ 4 f opt ≤ feed ≤ f opt , V T = f l 3 V 15 . Here, f opt is the largest ( optimum ) feed of the two feed/speed values given in the speed tables.
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