CFS Metric & Imperial Conversion 3

Question 1

What is the tensile stress area of an M12×1.75 bolt in mm²? (Use the formula: As = 0.7854 × (d - 0.9743/n)²)

Accepted Answer

84.3 mm²

Answer

For M12×1.75 the standard tensile stress area is 84.3 mm² per ISO 898 tables.

Question 2

Convert a clamping force of 10,000 N to pound-force (lbf).

Accepted Answer

2,248 lbf

Answer

1 N = 0.2248 lbf, so 10,000 N × 0.2248 = 2,248 lbf.

Question 3

A 3/8-16 UNC bolt has a pitch of how many millimeters?

Accepted Answer

1.588 mm

Answer

Pitch = 25.4 ÷ TPI = 25.4 ÷ 16 = 1.5875 mm ≈ 1.588 mm.

Question 4

An engineer specifies a surface finish of 1.6 μm Ra. What is the approximate equivalent in microinches (μin)?

Accepted Answer

63 μin

Answer

1 μm = 39.37 μin, so 1.6 μm × 39.37 ≈ 63 μin.

Question 5

A nut has a width-across-flats of 19 mm. Which standard inch wrench size is the closest fit?

Accepted Answer

3/4 inch (19.05 mm)

Answer

19 mm is nearly identical to 3/4 inch (19.05 mm), making it the closest standard inch wrench.

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