The required pressure for Force fit to assemble cylindrical parts not only depends on allowance but also the surface fitted area. Based on surface area the fitted pressure will increase in proportion to the distance that the inner surface bore/hub is pressed in. The approximate ultimate pressure (in tons) can be determined by using following formulae;

P = Required ultimate pressure, in tons,
A = Contacted surface area between Hole/bore and Shaft.
F = Pressure Factor
a = Total allowance, in inches

 Shaft Diameter (Inches) Pressure Factor (F) Shaft Diameter(Inches) Pressure Factor (F) 1.00 500 5.25 86 1.25 395 5.50 82 1.50 325 5.75 78 1.75 275 6.0 75 2.00 240 6.25 72 2.25 212 6.50 69 2.50 189 6.75 66 2.75 170 7.00 64 3.00 155 7.25 61 3.25 145 7.50 59 3.50 131 7.75 57 3.75 122 8.00 55 4.00 115 8.50 52 4.25 108 9.00 48.8 4.50 100 9.50 46.0 4.75 96 10.00 43.5 5.00 91 10.50 41.3

### Force and Shrink Limits and Fits For Cylindirical Parts [(ANSI B4.1-1967,R1987)]

All limits shown in chart below are in thousandths of an inches. Symbols H6,H7,s6, etc. are Shaft and Hole designations used in American-British-Canadian System (ABC). Limits for Shaft and Hole are applied algebraically to the Nominal (basic) size to obtain the limits of the size for the parts. All data given in bold in the chart below are in accordance with ABC agreements. The values given under the "Clearance Limits Column" represent min and max amounts of clearance resulting from application of standard tolerance limits.

 VALUES SHOWN BELOW ARE IN THOUSANDTHS OF AN INCHES Nominal (Basic) Size Renges (Inches) Class FN1 Class FN2 Class FN3 Class FN4 Class FN5 I n t e r f e r e n c e Limits Standard Tolerance Limits I n t e r f e r e n c e Limits Standard Tolerance Limits I n t e r f e r e n c e Limits Standard Tolerance Limits I n t e r f e r e n c e Limits Standard Tolerance Limits I n t e r f e r e n c e Limits Standard Tolerance Limits Over To Hole H6 Shaft HoleH7 Shafts6 HoleH7 Shaftt6 HoleH7 Shaftu6 HoleH8 Shaftx7 0 0.12 0.050.5 +0.250 +0.5+0.3 0.20.85 +0.40 +0.85+0.6 0.30.95 +.040 +0.95+0.7 0.31.3 +0.60 +1.3+0.9 0.12 0.24 0.10.6 +0.30 +0.6+0.4 0.20.1 +0.50 +1.0+0.7 0.41.2 +0.50 +1.2+0.9 0.51.7 +0.70 +1.7+1.2 0.24 0.40 0.10.75 +0.40 +0.75+0.5 0.41.4 +0.60 +1.4+1.0 0.61.6 +0.60 +1.6+1.2 0.52.0 +0.90 +2.0+1.4 0.40 0.56 0.10.8 +0.40 +0.8+0.5 0.51.6 +0.70 +1.6+1.2 0.71.8 +0.70 +1.8+1.4 0.62.3 +1.00 +2.3+1.6 0.56 0.71 0.20.9 +0.40 +0.9+0.6 0.51.6 +0.70 +1.6+1.2 0.71.8 +0.70 +1.8+1.4 0.82.5 +1.00 +2.5+1.8 0.71 0.95 0.21.1 +0.50 +1.1+0.7 .061.9 +0.80 +1.9+1.4 0.82.1 +0.8 +2.1+1.6 1.03.0 +1.20 +3.0+2.2 0.95 1.19 0.31.2 +0.50 +1.2+0.8 0.61.9 +0.80 +1.9+1.4 0.82.1 +0.80 +2.1+1.6 1.02.3 +0.80 +2.3+1.8 1.33.3 +1.20 +3.3+2.5 1.19 1.58 0.31.3 +0.60 +1.3+0.9 0.82.4 +1.00 +2.4+1.8 1.02.6 +1.00 +2.6+2.0 1.53.1 +1.00 +3.1+2.5 1.44.0 +1.60 +4.0+3.0 1.58 1.97 0.41.4 +0.60 +1.4+1.0 0.82.4 +1.00 +2.4+1.8 1.22.8 +1.00 +2.8+2.2 1.83.4 +1.0 +3.4+2.8 2.45.0 +1.6 +5.0+4.0 1.97 2.56 0.61.8 +0.70 +1.8+1.3 0.82.7 +1.20 +2.7+2.0 1.33.2 +1.20 +3.2+2.5 2.34.2 +1.20 +4.2+3.5 3.26.2 +1.80 +6.2+5.0 2.56 3.15 0.71.9 +0.70 +1.9+1.4 1.02.9 +1.20 +2.9+2.2 1.83.7 +1.20 +3.7+3.0 2.84.7 +1.0 +4.7+4.0 4.27.2 +1.80 +7.2+6.0 3.15 3.94 0.92.4 +0.90 +2.4+1.8 1.43.7 +1.40 +3.7+2.8 2.14.4 +1.40 +4.4+3.5 3.65.9 +1.40 +5.9+5.0 4.88.4 +2.20 +8.4-7.0 3.94 4.73 1.12.6 +0.90 +2.6+2.0 1.63.9 +1.0 +3.9+3.0 2.64.9 +1.40 +4.94.0 4.66.9 +1.40 +6.9+8.0 5.89.4 +2.20 +9.4+8.0 4.73 5.52 1.22.9 +1.00 +2.9+2.2 1.94.5 +1.60 +4.5+3.5 3.46.0 +1.60 +6.0+5.0 5.48.0 +1.60 +8.0+7.0 7.511.6 +2.50 +11.6+10.0 5.52 6.30 1.53.2 +1.00 +3.2+2.5 2.45.0 +1.60 +5.0+4.0 3.46.0 +1.60 +6.0+5.0 5.48.0 +1.60 +8.0+7.0 8.513.6 +2.50 +13.6+12.0 6.30 7.09 1.83.5 +1.00 +3.5+2.8 2.95.5 +1.60 +5.5+4.5 4.47.0 +1.60 +7.0+8.0 6.49.0 +1.60 +9.0+8.0 9.513.6 +2.50 +13.6+12.0 7.09 7.88 1.83.8 +1.20 +3.8+3.0 3.26.2 +1.80 +6.2+5.0 5.28.2 +1.80 +8.2+7.0 7.210.2 +1.80 +10.2+9.0 112.215.8 +2.80 +15.8+14.0 7.88 8.86 2.34.3 +1.20 +4.3+3.5 3.26.2 +1.80 +6.2+5.0 5.28.2 +1.80 +8.2+7.0 8.211.2 +1.80 +11.2+10.0 13.217.8 +2.80 +17.8+16.0 8.86 9.85 2.34.3 +1.20 +4.3+3.5 4.27.2 +1.80 +7.2+6.0 6.29.2 +1.80 +9.2+8.0 10.213.2 +1.80 +13.2+12.0 13.217.8 +2.80 +17.8+16.0 9.85 11.03 2.84.9 +1.20 +4.9+4.0 4.07.2 +2.00 +7.2+6.0 7.010.2 +2.00 +10.2+9.0 10.013.2 +2.00 +13.2+12.0 15.020.0 +3.00 +20.0+18.0 11.03 12.41 2.84.9 +1.20 +4.9+4.0 5.08.2 +2.00 +8.2+7.0 7.010.2 +2.00 +10.2+9.0 12.015.2 +2.00 +15.2+14.0 17.022.0 +3.00 +22.0+20.0 12.41 13.98 3.15.5 +1.40 +5.5+4.5 5.89.4 +2.20 +9.4+8.0 7.811.4 +2.20 +11.4+10.0 13.817.4 +2.20 +17.4+16.0 18.524.2 +3.50 +24.2+22.0 13.98 15.75 3.66.1 +1.40 +6.1+5.0 5.89.4 +2.20 +9.48.0 9.813.4 +2.20 +13.4+12.0 15.819.4 +2.20 +19.4+18.0 21.527.2 +3.50 +27.2+25.0 15.75 17.72 4.47.0 +1.60 +7.0+6.0 6.510.6 +2.50 +10.6+9.0 9.513.6 +2.50 +13.6+12.0 7.521.6 +2.50 +21.6+20.0 24.030.5 +4.00 +30.5+28.0 17.72 19.69 4.47.0 +1.60 +7.0+6.0 7.511.6 +2.50 +11.6+10.0 11.515.6 +2.50 +15.6+14.0 19.523.6 +2.50 +23.6+22.0 26.032.5 +4.00 +32.5+30.0 19.69 24.34 6.09.2 +2.00 +9.2+8.0 9.014.0 +3.00 +14.0+12.0 15.020.0 +3.0 +20.0+18.0 22.027.0 +3.00 +27.0+25.0 30.038.0 +5.00 +38.0+35.0 24.34 30.09 7.010.2 +2.00 +10.2+9.0 11.016.0 +3.00 +16.0+14.0 17.022.0 +3.0 +22.0+20.0 27.032.0 +3.00 +32.0+30.0 35.043.0 +5.00 +43.0+40.0 30.09 35.47 7.511.6 +2.50 +11.6+10.0 14.020.5 +4.0 +20.5+18.0 21.027.5 +4.00 +27.5+25.0 31.037.5 +4.00 +37.5+35.0 44.054.0 +6.00 +54.0+50.0 35.47 41.49 9.513.6 +2.50 +13.6+12.0 16.022.5 +4.00 +22.5+20.0 24.030.5 +4.00 +30.5+28.0 36.043.5 +4.00 +43.5+40.0 54.064.0 +6.00 +64.0+60.0 41..49 48.28 11.016.0 +3.00 +16.0+14.0 17.025.0 +5.00 +25.0+22.0 30.038.0 +5.00 +38.0+35.0 45.053.0 +5.00 +53.0+50.0 62.075.0 +8.00 +75.0+70.0 48.28 56.19 13.018.0 +3.00 +18.0+16.0 20.028.0 +5.00 +28.0+25.0 35.043.0 +5.00 +43.0+40.0 55.063.0 +5.00 +63.0+60.0 72.085.0 +8.00 +85.0+80.0 56.19 65.54 14.020.5 +4.00 +20.5+18.0 24.034.0 +6.00 +34.0+30.0 39.049.0 +6.00 +49.0+45.0 64.074.0 +6.00 +74.070.0 90.0106.0 +10.00 +106.0+100.0 65.54 76.39 18.024.5 +4.00 +24.5+22.0 29.039.0 +6.00 +39.0 +35.0 44.054.0 +6.00 +54.0+50.0 74.084.0 +6.00 +84.0+80.0 110126 +10.00 +126.0+120.0 76.39 87.79 20.028.0 +5.00 +28.0+25.0 32.045.0 +8.00 +45.0+40.0 52.065.0 +8.00 +65.0+60.0 82.095.0 +8.00 +95.0+90.0 128148 +12.00 +148.0+140.0 87.79 100.9 23.031.0 +5.00 +31.0+28.0 37.050.0 +8.00 +50.0+45.0 62.075.0 +8.00 +75.0+70.0 92.0105 +8.00 +105+100 148168 +12.00 +168.0+160.0 100.9 115.3 24.034.0 +6.00 +34.0+30.0 40.056.0 +10.00 +56.0+50.0 70.086.0 +10.00 +86.0+80.0 110126 +10.00 +126+120 164190 +16.00 +190.0+180.0 115.3 131.9 29.039.0 +6.00 +39.0+35.0 50.066.0 +10.00 +66.0+60.0 80.096.0 +10.00 +96.0+90.0 130146 +10.00 +146+140 184210 +16.00 +210.0+200.0 131.9 152.2 37.050.0 +8.00 +50.0+45.0 58.078.0 +12.00 +78.0+70.0 88.0108 +12.00 +108+100 148168 +12.00 +168+160 200232 +20.00 +232.0+220.0 152.2 171.9 42.055.0 +8.00 +55.0+50.0 68.088.0 +12.00 +88.0+80.0 108128 +12.00 +128+120 168188 +12.00 +188+180 230262 +20.00 +262.0+250.0 171.9 200 50.066.0 +10.00 +66.0+60.0 74.0100 +16.00 +100+90 124150 +16.00 +150+140 184210 +16.00 +210+200 275316 +25.00 +316.0+300.0

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