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INERTIA CHART
I=WR2 of Steel (per inch of length)
DIA. (IN.)

WR2
(LB.-IN.2)

 DIA. (IN.) WR 2
(LB.-IN.2)		 DIA. (IN.) WR 2
(LB.-IN.2)
1/4 .00011 8-3/4 162.72 29 19589.76
5/16 .00027 9 182.88 30 22452.48
3/8 .00055 9-1/4 203.04 31 25598.88
7/16 .00102 9-1/2 233.20 32 29059.2
1/2 .00173 9-3/4 252.00 33 32860.8
9/16 .00279 10 277.92 34 37036.8
5/8 .00425 10-1/4 306.72 35 41587.2
11/16 .00623 10-1/2 338.4 36 46540.8
3/4 .00864 10-3/4 371.52 37 51940.8
13/16 .01215 11 407.52 38 57787.2
7/8 .01634 11-1/4 444.96 39 64123.2
15/16 .02154 11-1/2 486.72 40 70963.2
1 .0288 11-3/4 592.92 40 78321.6
1-1/4 .0720 12 576.00 42 86227.2
1-1/2 .144 12-1/4 626.10 43 94766.4
1-3/4 .288 12-1/2 679.88 44 103881.6
2 .432 14-3/4 735.84 45 113659.2
2-1/4 .720 13 803.52 46 124099.2
2-1/2 1.152 13-1/4 858.24 47 135259.2
2-3/4 1.584 13-1/2 924.48 48 147139.2
3 2.304 13-3/4 995.04 49 159782.4
3-1/2 4.176 14 1068.48 50 173246.4
3-3/4 5.472 14-1/4 1147.68 51 187516.8
4 7.056 14-1/2 1229.76 52 202665.6
4-1/4 9.072 14-3/4 1317.60 53 218707.2
4-1/2 11.376 15 1404.00 54 235684.8
5 17.280 16 1815.84 55 253641.6
5-1/2 25.488 17 2314.08 56 272606.4
6 36.000 18 2910.24 57 292593.6
6-1/4 42.624 19 3611.52 58 313675.2
6-1/2 49.680 20 4433.76 59 335880.0
6-3/4 57.888 21 5389.92 60 359238.8
7 66.816 22 6492.96 66 525960.0
7-1/4 77.040 23 7757.28 72 744768.0
7-1/2 87.984 24 9195.84 78 1026000.0
7-3/4 100.656 25 10827.36 84 1380069.0
8 113.904 26 12666.24 90 1818576.0
8-1/4 128.880 27 14731.20 96 2354256.0
8-1/2 144.00 28 17036.64 102 3000384.0
NOTES:
1. To determine WR2 of a given shaft, multiply the WR2 given above by the length of the shaft or the thickness of the disc in inches.
2. For hollow shafts, subtract WR2 of ID from WR2 of OD and multiply by length.
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INERTIA CONVERSION CHART
To determine the inertia of a rotating member of a material other than steel, multiply the inertia of the steel diameter from the Inertia Chart at left by:
MATERIAL MULTIPLIER
Bronze 1.05
Steel 1.00
Iron 0.92
Powdered Bronze 0.79
Powdered Metal Iron 0.88
Aluminum 0.35
Nylon 0.17

 

FULL LOAD RUNNING
Torque of Motors in Lb.-In.
HP 3450 RPM 1750 RPM 1150 RPM 870 RPM
1/50 0.365 0.720 1.096 1.448
1/20 0.913 1.800 2.739 3.621
1/12 1.521 3.000 4.563 6.032
1/8 2.283 4.500 6.848 9.051
1/6 3.044 6.000 9.148 12.09
1/4 4.565 9.000 13.70 18.10
1/3 6.081 12.00 18.24 24.11
1/2 9.130 18.00 27.39 36.21
3/4 13.70 27.00 41.09 54.31
1 18.26 36.00 54.78 72.41
1-1/2 27.39 54.00 82.17 108.60
2 36.52 72.00 109.56 144.80
3 54.78 108.00 164.30 217.20
5 91.30 180.00 273.96 362.00
7-1/2 137.00 270.00 410.80 543.10
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INERTIA
TO CONVERT FROM TO MULTIPLY BY
g-cm 2 lb.-in. 2 3.417 x 10 -4
g-cm2 lb.-ft.2 2.373 x 10-6
kg-cm2 lb.-in.2 3.417 x 10-1
kg-cm-sec2 lb.-in.2 335.1
N-m-sec2 lb.-in.2 3417
kg-m2 lb.-in.2 3417
N-m2 lb.-in.2 348.47
lb.-in.2 kg-cm2 2.926
lb.-in.2 kg-m2 2.9265 x 10-4
lb.-in.2 N-m2 2.870 x 10-3
lb.-in.2 lb.-in.-sec2 2.590 x 10-3
lb.-in.2 lb.-ft.2 6.944 x 10-3
lb.-in.2 oz.-in.2 16
lb.-ft.2 lb.-in.2 144
lb.-ft.2 oz.-in.2 2304
lb.-ft.2 oz.-in.-sec2 5.969
oz.-in.2 oz.-in.-sec2 2.590 x 10-3
oz.-in.2 lb.-in.2 6.25 x 10-2
oz.-in.-sec2 oz.-in.2 3.8609 x 10-2
oz.-in.-sec2 lb.-in.2 24.125
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TORQUE
TO CONVERT FROM TO MULTIPLY BY
kg-m lb.-in. .6026
N-m lb.-in. 8.850
N-m oz.-in. 141.69
lb.-in. g-cm 1152
lb.-in. kg-cm 1.152
lb.-in. kg-m 1.6596
lb.-in. N-m .1130
lb.-in. oz.-in. 16.0
lb.-in. lb.-ft.. .083
lb.-ft. lb.-in. 12.0
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MISCELLANEOUS
TO CONVERT FROM TO MULTIPLY BY
horsepower ft.-lb./min. 33,000
kilograms pounds 2.2
meters millimeters 1000
millimeters inches 3.937 x 10-3
Newtons pounds .225
radians degrees 57.3
revolutions radians 6.283
revolutions/min. degrees/sec. 6
square-inches square-millimeters 645.2
temp. (°C) +17.78 temp. (° F) 1.8
temp. (°F)-32 temp. (° C) 5/9
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