Modified Stock Gearing - Boston Gear

Spur Gears
Approximate Horsepower and Torque* Ratings
For Class I Service (Service Factor = 1.0)
20 DIAMETRAL PITCH STEEL 14 1 ⁄2° PRESSURE ANGLE 3/8" FACE REFERENCE PAGE 20.
No. 25 RPM 50 RPM 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM 3600 RPM
Teeth H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque
11 .01 21.6 .02 21.4 .03 21.2 .07 20.7 .10 20.2 .18 18.9 .25 17.8 .32 16.8 .43 15.1 .66 11.6
12 .01 23.5 .02 23.4 .04 23 .07 22.5 .10 21.9 .19 20.5 .27 19.2 .34 18 .46 16.1 .70 12.2
13 .01 26.9 .02 26.8 .04 26.4 .08 25.7 .12 25 .22 23.2 .31 21.6 .39 20.3 .51 17.9 .77 13.4
14 .01 30.7 .02 30.5 .05 30 .09 29.1 .13 28.3 .25 26.1 .35 24.2 .43 22.6 .57 20 .84 14.7
15 .01 34.2 .03 33.9 .05 33.4 .10 32.3 .15 31.4 .27 28.8 .38 26.6 .47 24.7 .62 21.7 .90 15.8
16 .02 37.8 .03 37.5 .06 36.8 .11 35.7 .16 34.5 .30 31.6 .41 29 .51 26.9 .67 23.4 .97 16.9
18 .02 45.1 .04 44.7 .07 43.8 .13 42.3 .19 40.8 .35 36.9 .48 33.7 .59 31 .76 26.7 1.08 18.9
20 .02 52.4 .04 51.9 .08 50.8 .15 48.7 .22 46.9 .40 42 .54 38 .66 34.8 .85 29.7 1.18 20.6
22 .02 59.5 .05 58.8 .09 57.5 .17 54.9 .25 52.7 .45 46.8 .60 42 .73 38.2 .92 32.3 1.26 22.1
24 .03 66.3 .05 65.4 .10 63.8 .19 60.8 .28 58 .49 51.1 .65 45.6 .78 41.2 .99 34.6 1.33 23.3
25 .03 70.5 .06 69.5 .11 67.7 .20 64.4 .29 61.4 .51 53.8 .68 47.9 .82 43.1 1.03 36 1.38 24.0
28 .03 81.2 .06 80 .12 77.7 .23 73.4 .33 69.7 .57 60.3 .76 53.2 .91 47.5 1.12 39.2 1.47 25.7
30 .03 87.8 .07 86.4 .13 83.7 .25 78.9 .36 74.6 .61 64 .80 56.1 .95 50 1.17 40.9 1.52 26.6
32 .04 96.3 .08 94.7 .15 91.6 .27 86 .39 81 .66 69.1 .86 60.2 1.02 53.3 1.24 43.4 1.59 27.8
35 .04 107 .08 105 .16 101 .30 94.7 .42 88.9 .71 74.9 .92 64.7 1.09 57 1.31 46 1.66 29.1
36 .04 110 .09 108 .17 104 .31 97.1 .43 91 .73 76.4 .94 65.8 1.10 57.8 1.33 46.5 1.68 29.3
40 .05 124 .10 122 .19 117 .34 108 .48 101 .79 83.5 1.02 71.2 1.18 62.1 1.41 49.4 1.75 30.7
48 .06 151 .12 148 .22 141 .41 128 .56 118 .91 95.4 1.14 80 1.31 69.8 1.54 53.8
50 .06 158 .12 154 .23 146 .42 133 .58 122 .93 98 1.17 81.7 1.34 70.1 1.56 54.6
60 .08 193 .15 187 .28 176 .50 158 .68 143 1.06 112 1.31 91.6 1.48 77.6 1.70 59.5
64 .08 209 .16 203 .30 190 .54 169 .73 153 1.12 118 1.37 96 1.54 80.9
A
20 DIAMETRAL PITCH CAST IRON 14 1 ⁄2° PRESSURE ANGLE 3/8" FACE REFERENCE PAGE 21.
No. 25 RPM 50 RPM 100 RPM 200 RPM 300 RPM 600 RPM 900 RPM 1200 RPM 1800 RPM 3600 RPM
Teeth H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque H.P. Torque
70 .05 137 .10 132 .20 123 .35 109 .46 97.5 .71 74.2 .86 60 .96 50.2
72 .06 140 .11 136 .20 126 .35 111 .47 99.4 .72 75.3 .87 60.6 .97 50.7
80 .06 158 .12 152 .22 141 .39 123 .52 108 .77 80.7 .92 64.3 1.02 53.4
84 .07 166 .13 159 .23 147 .40 127 .53 112 .79 82.7 .94 65.5 1.03 54.3
90 .07 177 .13 169 .25 155 .42 133 .56 117 .81 85.4 .96 67.2
96 .07 189 .14 180 .26 164 .44 140 .58 122 .84 87.9 .98 68.8
100 .08 196 .15 186 .27 170 .46 144 .59 125 .85 89.5 1.00 69.7
112 .09 222 .17 210 .30 189 .50 158 .65 136 .91 95.5 1.05 73.6
120 .09 237 .18 223 .32 200 .53 166 .67 141 .93 98.1 1.07 75.1
140 .11 273 .20 255 .36 225 .58 183 .73 153 .99 104
144 .11 281 .21 262 .37 230 .59 186 .74 156 1.00 105
160 .13 317 .23 294 .41 256 .64 203 .80 168 1.06 111
180 .14 353 .26 324 .44 278 .69 217 .85 178 1.10 115
200 .15 388 .28 354 .48 300 .73 230 .89 187 1.13 119
Ratings are based on strength calculation. Basic static strength rating, or for hand operation of above gears is approximately 3 times the 100 RPM rating.
NOTE: Ratings to right of heavy line are not recommended, as pitch line velocity exceeds 1000 feet per minute.
They should be used for interpolation purposes only.
*Torque Ratings (Lb. Ins.).
P-1930-BG 04/10 Boston Gear 800-825-6544 51