Question

Question 1 (30 points) Explain the meaning of the geometrical tolerances, for views of the mechanical components shown in the first column 7.5 points 150 0.003 7.5 points B Sectional view from the front 0.3 B

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Answer 1

Geometrical tolerences means the permissible variation in the dimension of the geometry.

1. In first geometry the dia of the shaft is given in geometry is 1.50 units with the tolerence of -0.003 units. It means that the actual diameter of the part after manufacturing should not exeed 1.50 units and should not be less than 1.50-0.003= 1.497 units. Max Allowed Dia= 1.50 unit, Min Allowed Dia= 1.497 units

2. In second geometry the tolerence if inside dia of hole is given 0.3 unit. It means the allowable variation in the dimension is 0.3 unit. It is in both side positive and negative. Max allowed dia is= Actual Dia + 0.3, Min Allowed dia= Actual Dia - 0.3 units.

3. In third geometry angular tolerence is provided. The actual angular dimension of the part is 40 degree whereas the permissible variation in angle is 0.8 degree it means the angle can varry between 39.2<A<40.8 degree.

4. In 4th geometry two types of tolerences are given one is 0.750 +- 0.030, it means the allowed dimension varry between 0.720 to 0.780. Whereas the second dimension is 1.000 (+0.00, -0.010) It means it calue should not exeeds 1.000 but can be reduced upto 0.990 i.e. the allowed dimension is lie between 1.000 to 0.990 units.

In this one more tolerenceis given which is 0.014 A-B it means that the perpendicular distance between surface A and B should not be more than 0.014 units.