Table 22. Diameter Speed and Feed Adjustment Factors for HSS Twist Drills and Reamers Cutting Speed, V = V opt 3 F f 3 F d
Ratio of Chosen Feed to Optimum Feed Tool Diameter 0.08 in 0.15 in 0.25 in 0.40 in 0.60 in 1.00 in 2.00 in 3.00 in 4.00 in 1.00 1.25 1.50 2.00 2.50 3.00 4.00 (2 mm) (4 mm) (6 mm) (10 mm) (15 mm) (25 mm) (50 mm) (75 mm) (100 mm) Feed Factor, F f Diameter Factor, F d 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30 0.44 0.56 0.78 1.00 1.32 1.81 2.11 2.29 0.90 1.00 1.06 1.09 1.14 1.18 1.21 1.27 0.32 0.46 0.59 0.79 1.00 1.30 1.72 1.97 2.10 0.80 1.00 1.12 1.19 1.31 1.40 1.49 1.63 0.34 0.48 0.61 0.80 1.00 1.27 1.64 1.89 1.95 0.70 1.00 1.15 1.30 1.50 1.69 1.85 2.15 0.38 0.52 0.64 0.82 1.00 1.25 1.52 1.67 1.73 0.60 1.00 1.23 1.40 1.73 2.04 2.34 2.89 0.42 0.55 0.67 0.84 1.00 1.20 1.46 1.51 1.54 0.50 1.00 1.25 1.50 2.00 2.50 3.00 5.00 0.47 0.60 0.71 0.87 1.00 1.15 1.30 1.34 1.94 0.40 1.00 1.23 1.57 2.29 3.08 3.92 5.70 0.53 0.67 0.77 0.90 1.00 1.10 1.17 1.16 1.12 0.30 1.00 1.14 1.56 2.57 3.78 5.19 8.56 0.64 0.76 0.84 0.94 1.00 1.04 1.02 0.96 0.90 0.20 1.00 0.90 1.37 2.68 4.49 6.86 17.60 0.83 0.92 0.96 1.00 1.00 0.96 0.81 0.73 0.66 0.10 1.00 1.44 0.80 2.08 4.36 8.00 20.80 1.29 1.26 1.21 1.11 1.00 0.84 0.60 0.46 0.38 Ratio of the two cutting speeds ( average / optimum ) given in the tables V avg / V opt This table is specifically for use with the combined feed/speed data for HSS twist drills in Table 17 through Table 23; use Table 5a and Table 5b to adjust speed and tool life for indexable insert drilling with carbides. The combined feed/speed data for HSS twist drilling are based on a 0.60-inch diameter HSS drill with standard drill point geometry (2-flute with 118 ° tip angle). To adjust the given speeds for different feeds and drill diameters, 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 from the speed table), and the ratio of the two cutting speeds V avg / V opt . Use the values 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 diameter 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 drill diameter. For diameters not given, interpolate between the nearest available sizes. 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). Tool life using the selected feed and the adjusted speed should be approximately 45 minutes. Speed adjustment factors to modify tool life are found in Table 15e.
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