Millwright Certification Blueprint Reading 2

Question 1

On a mechanical drawing, what does a centerline (alternating long and short dashes) through a circular feature indicate?

Accepted Answer

The axis of symmetry for the feature

Answer

Centerlines show the axis of symmetry for circular features like holes, shafts, and bores, and are essential for dimensioning and locating features.

Question 2

What does the welding symbol designation 'E7018' tell a millwright about the electrode?

Accepted Answer

It has 70,000 PSI tensile strength, all-position, low-hydrogen

Answer

In E7018: E=electrode, 70=70,000 PSI minimum tensile strength, 1=all-position capability, 8=low-hydrogen potassium with iron powder coating and AC/DC current.

Question 3

In GD&T, what does the position tolerance symbol (a crosshair within a circle) control?

Accepted Answer

The location of a feature relative to datum references

Answer

The position tolerance controls how far a feature's actual center may deviate from its true (theoretically exact) position relative to specified datum references.

Question 4

What information does a section view on a mechanical drawing provide that a standard view cannot?

Accepted Answer

Internal features and material thickness revealed by an imaginary cut

Answer

Section views show the internal structure of a part by depicting it as if cut along a plane, revealing hidden features, wall thicknesses, and internal passages that would otherwise be shown as hidden lines.

Question 5

A dimension on a drawing reads '25.00 plus or minus 0.05'. What is the total tolerance range for this dimension?

Accepted Answer

0.10 mm

Answer

The bilateral tolerance of plus or minus 0.05 means the acceptable range is from 24.95 to 25.05, giving a total tolerance range of 0.10 mm.

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Millwright Certification Blueprint Reading 2