Modified Stock Gearing - Boston Gear

Spur Gears
Approximate Horsepower and Torque* Ratings
For Class I Service (Service Factor = 1.0)
8 DIAMETRAL PITCH CAST IRON 20° PRESSURE ANGLE 1-1/2" FACE REFERENCE PAGE 45.
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
40 .84 2111 1.59 2007 2.90 1928 4.92 1550 6.40 1345 9.18 964 10.72 751
44 .95 2384 1.79 2256 3.23 2038 5.42 1707 6.99 1469 9.86 1035 11.41 799
48 1.03 2587 1.93 2437 3.47 2184 5.74 1809 7.35 1543 10.20 1072 11.72 821
56 1.22 3080 2.28 2876 4.03 2539 6.53 2057 8.23 1729 11.14 1170
60 1.30 3283 2.42 3052 4.25 2676 6.81 2146 8.53 1792 11.40 1198
64 1.42 3588 2.64 3322 4.59 2892 7.29 2297 9.07 1905 12.00 1260
72 1.59 3997 2.91 3669 5.00 3151 7.80 2458 9.59 2014 12.44 1307
80 1.79 4525 3.27 4119 5.54 3493 8.50 2679 10.34 2173 13.20 1386
88 1.96 4929 3.53 4451 5.92 3729 8.93 2816 10.76 2262 13.54 1422
96 2.11 5325 3.79 4772 6.27 3952 9.33 2941 11.15 2341 13.83 1453
112 2.49 6266 4.39 5533 7.11 4483 10.31 3250 12.13 2549
120 2.64 6651 4.63 5830 7.42 4677 10.63 3351 12.43 2610
128 2.79 7028 4.85 6118 7.71 4860 10.93 3444 12.69 2667
A
6 DIAMETRAL PITCH STEEL 20° PRESSURE ANGLE 2" FACE REFERENCE PAGE 45 & 46.
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
12 .63 1559 1.24 1565 2.38 1502 4.41 1391 6.16 1294 10.20 1072 13.06 915 15.19 798 18.14 635
14 .83 2097 1.62 2046 3.10 1951 5.67 1786 7.84 1647 12.70 1334 16.02 1122 18.42 967 21.67 759
15 .93 2345 1.81 2284 3.45 2171 6.27 1977 8.64 1814 13.85 1455 17.35 1215 19.85 1043 23.20 812
16 1.01 2551 1.97 2480 3.73 2351 6.76 2129 9.26 1945 14.71 1545 18.30 1282 20.85 1095 24.21 848
18 1.18 2981 2.29 2889 4.32 2722 7.74 2440 10.52 2210 16.41 1724 20.18 1413 22.79 1197 26.18 917
21 1.46 3671 2.81 3541 5.25 3306 9.26 2919 12.44 2613 18.93 1988 22.91 1605 25.61 1345
24 1.70 4294 3.27 4122 6.05 3815 10.54 3322 14.00 2941 20.83 2188 24.88 1743 27.56 1448
27 1.98 4986 3.78 4763 6.94 4372 11.92 3755 15.66 3241 22.85 2400 26.98 1889
30 2.25 5660 4.27 5381 7.77 4899 13.18 4155 17.17 3607 24.60 2584 28.75 2013
6 DIAMETRAL PITCH CAST IRON 20° PRESSURE ANGLE 2" FACE REFERENCE PAGE 46.
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
33 1.53 3847 2.89 3641 5.22 3288 8.74 2755 11.28 2370 15.90 1670 18.42 1290
36 1.71 4316 3.23 4066 5.78 3644 9.58 3018 12.26 2575 17.02 1788 19.56 1370
42 2.04 5148 3.81 4807 6.73 4244 10.91 3439 13.76 2891 18.62 1955
48 2.38 6009 4.41 5563 7.68 4843 12.21 3847 15.19 3191 20.09 2111
54 2.74 6899 5.02 6333 8.63 5440 13.46 4243 16.55 3477 21.48 2256
60 3.01 7591 5.48 6910 9.30 5860 14.26 4494 17.35 3645 22.14 2326
66 3.38 8515 6.10 7691 10.22 6443 15.44 4864 18.60 3907 23.39 2457
72 3.65 9200 6.54 8245 10.83 6827 16.12 5080 19.26 4045 23.90 2511
84 4.30 10835 7.59 9566 12.30 7752 17.83 5620 20.98 4407
96 4.82 12152 8.39 10579 13.33 8404 18.90 5955 21.95 4611
108 5.47 13800 9.40 11583 14.67 9245 20.37 6420 23.41 4917
120 5.97 15059 10.13 12770 15.54 9793 21.20 6680
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 61