Machinery's Handbook, 31st Edition
1104 TURNING-SPEED ADJUSTMENT FACTORS Table 5c. Cutting-Speed Adjustment Factors for Turning with HSS Tools Feed Feed Factor Depth of Cut Depth-of-Cut Factor in. mm F f in. mm F d 0.002 0.05 1.50 0.005 0.13 1.50 0.003 0.08 1.50 0.010 0.25 1.42 0.004 0.10 1.50 0.016 0.41 1.33 0.005 0.13 1.44 0.031 0.79 1.21 0.006 0.15 1.34 0.047 1.19 1.15 0.007 0.18 1.25 0.062 1.57 1.10 0.008 0.20 1.18 0.078 1.98 1.07 0.009 0.23 1.12 0.094 2.39 1.04 0.010 0.25 1.08 0.100 2.54 1.03 0.011 0.28 1.04 0.125 3.18 1.00 0.012 0.30 1.00 0.150 3.81 0.97 0.013 0.33 0.97 0.188 4.78 0.94 0.014 0.36 0.94 0.200 5.08 0.93 0.015 0.38 0.91 0.250 6.35 0.91 0.016 0.41 0.88 0.312 7.92 0.88 0.018 0.46 0.84 0.375 9.53 0.86 0.020 0.51 0.80 0.438 11.13 0.84 0.022 0.56 0.77 0.500 12.70 0.82 0.025 0.64 0.73 0.625 15.88 0.80 0.028 0.71 0.70 0.688 17.48 0.78 0.030 0.76 0.68 0.750 19.05 0.77 0.032 0.81 0.66 0.812 20.62 0.76 0.035 0.89 0.64 0.938 23.83 0.75 0.040 1.02 0.60 1.000 25.40 0.74 0.045 1.14 0.57 1.250 31.75 0.73 0.050 1.27 0.55 1.250 31.75 0.72 0.060 1.52 0.50 1.375 34.93 0.71 For use with HSS tool data only from Table 1 through Table 9. Adjusted cutting speed V = V HSS 3 F f 3 F d , where V HSS is the tabular speed for turning with high-speed tools. Example 3, Turning: Determine the cutting speed for turning 1055 steel of 175 to 225 BHN (Brinell Hardness Number) using a hard ceramic insert, a 15 ° lead angle, a 0.04-inch depth of cut and 0.0075 in/rev feed. The two feed/speed combinations given in Table 5a for 1055 steel are 15 ∕ 1610 and 8 ∕ 2780, corresponding to 0.015 in/rev at 1610 fpm and 0.008 in/rev at 2780 fpm, respectively. In Table 5a, the feed factor F f = 1.75 is found at the intersection of the row corresponding to feed/ f opt = 7.5 ∕ 15 = 0.5 and the column corresponding to V avg / V opt = 2780 ∕ 1610 = 1.75 (approximately). The depth-of-cut factor F d = 1.23 is found in the same row, under the column heading for a depth of cut = 0.04 inch and lead angle = 15 ° . The adjusted cutting speed is V = 1610 3 1.75 3 1.23 = 3466 fpm. Example 4, Turning: The cutting speed for 1055 steel calculated in Example 3 represents the speed required to obtain a 15-minute tool life. Estimate the cutting speed needed to obtain a tool life of 45, 90, and 180 minutes using the results of Example 3. To estimate the cutting speed corresponding to another tool life, multiply the cutting speed for 15-minute tool life V 15 by the adjustment factor from the Table 5b, Tool Life Factors for Turning. This table gives three factors for adjusting tool life based on the feed used, f s for feeds less than or equal to 1 ∕ 2 f opt , f m for midrange feeds between 1 ∕ 2 and 3 ∕ 4 f opt and f l for large feeds greater than or equal to 3 ∕ 4 f opt and less than f opt . In Example 3, f opt is 0.015 in/rev and the selected feed is 0.0075 in/rev = 1 ∕ 2 f opt . The new cutting speeds for the various tool lives are obtained by multiplying the cutting speed for 15-minute tool life V 15 by the factor for small feeds f s from the column for turning with ceramics in Table 5b. These calculations, using the cutting speed obtained in Example 3, follow.
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