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Fraction & Metric sizes of drills conversion table
Inches and millimeteres
(a) Inches to millimteres Basic: 1 inch = 25.4 millimetres
Inch 0 1/16 1/8 3/16 1/4 5/16 3/8 7/16
0 1.59 3.18 4.76 6.35 7.94 9.53 11.11
1 25.40 26.98 25.58 30.16 31.75 33.34 34.93 36.51
2 50.80 52.39 53.97 55.56 57.15 58.74 60.33 61.91
3 76.20 77.79 79.38 80.96 82.55 84.14 85.73 87.31
4 101.60 103.19 104.78 106.36 107.95 109.54 111.13 112.71
5 127.00 128.59 130.18 131.76 133.35 134.94 136.53 138.11
6 152.40 153.99 155.58 157.16 158.75 160.34 161.93 163.51
7 177.80 179.39 180.98 182.56 184.15 185.74 187.33 188.91
8 203.20 204.79 206.38 207.96 209.55 211.14 212.73 214.31
9 228.60 230.19 231.78 233.36 234.95 236.54 238.13 239.71
10 254.00 255.59 257.18 258.76 260.35 261.94 263.53 265.11
Inch 1/2 9/16 5/8 11/16 3/4 13/16 7/8 15/16
0 12.70 14.29 15.88 17.46 19.05 20.64 22.23 23.81
1 38.10 39.69 41.28 42.86 44.45 46.04 47.63 49.21
2 63.50 65.09 66.68 68.26 69.85 71.44 73.03 74.61
3 88.90 90.49 92.08 93.66 95.25 96.84 98.43 100.01
4 114.30 115.89 117.48 119.06 120.65 122.24 123.83 125.41
5 139.70 141.29 142.88 144.46 146.05 147.64 149.23 150.81
6 165.10 166.69 168.28 169.86 171.45 173.04 174.63 176.21
7 190.50 192.09 193.68 195.26 196.85 198.44 200.03 201.61
8 215.90 217.49 219.08 220.66 222.25 223.84 225.43 227.01
9 241.30 242.89 244.48 246.06 247.65 249.24 250.83 252.41
10 266.70 268.29 269.88 271.46 273.05 274.64 276.23 277.81

Example: 25 3/4” = 20’ = (10 x 2” = 10 x 50.8 =) 508.00 = 654.05 mm
5 3/4” =
146.05

(b) Millimteres to Inches Basic: 1 Millimetre = 0.039369 inch
mm 0 1 2 3 4 5 6 7 8 9
0 0.039 0.079 0.118 0.157 0.197 0.236 0.276 0.315 0.354
10 0.394 0.433 0.472 0.512 0.551 0.591 0.630 0.669 0.700 0.748
20 0.787 0.827 0.866 0.905 0.945 0.984 1.024 1.063 1.102 1.142
30 1.181 1.220 1.259 1.299 1.338 1.378 1.417 1.457 1.496 1.535
40 1.575 1.614 1.653 1.693 1.732 1.772 1.811 1.850 1.890 1.929
50 1.968 2.007 2.047 20.87 2.126 2.165 2.205 2.244 2.283 2.323
60 2.362 2.401 2.441 2.480 2.520 2.559 2.598 2.638 2.677 2.716
70 2.756 2.795 2.835 2.874 2.913 2.953 2.992 3.031 3.074 3.110
80 3.149 3.189 3.228 3.268 3.307 3.346 3.386 3.425 3.464 3.504
90 3.543 3.583 3.622 3.661 3.701 3.740 3.779 3.819 3.858 3.897
mm 0 100 200 300 400 500 600 700 800 900
0 3.94 7.87 11.81 15.75 19.68 23.62 27.56 31.49 35.43
1000 39.37 43.30 47.24 51.18 55.12 59.05 62.99 66.93 70.86 74.80
2000 78.74 82.67 86.61 90.55 94.48 98.42 102.36 106.30 110.23 114.17
3000 118.11 122.04 125.98 129.92 133.85 137.79 141.73 145.66 149.60 153.54
4000 157.47 161.41 165.35 169.20 173.22 177.16 181.10 185.03 188.97 192.91
5000 196.84 204.71 212.59 220.38 228.34 236.21 244.09 251.96 259.83 267.71

Example: 2256 mm = 2200 mm = 86.61”
56 mm = 2.204”

298 £_õ & Gm: @©hPo (NSQF - Revised 2022) ------ R.T. for Ex. No.1.5.72-73