CFS Metric & Imperial Conversion 2 — Questions and Answers
Question 1: A bolt has a shank diameter of 12 mm. What is the closest standard inch fractional size?
- 1/2 inch (12.70 mm) (Correct answer)
- 15/32 inch (11.91 mm)
- 7/16 inch (11.11 mm)
- 9/16 inch (14.29 mm)
Correct answer: 1/2 inch (12.70 mm)
12 mm converts to approximately 0.472 inches, and 1/2 inch (0.500 in / 12.70 mm) is the closest standard size.
Question 2: Convert a torque value of 100 N·m to foot-pounds (ft·lbf).
- 73.8 ft·lbf (Correct answer)
- 88.5 ft·lbf
- 113.0 ft·lbf
- 56.0 ft·lbf
Correct answer: 73.8 ft·lbf
1 N·m equals 0.7376 ft·lbf, so 100 N·m × 0.7376 = 73.76 ft·lbf ≈ 73.8 ft·lbf.
Question 3: A fastener specification lists a proof load stress of 120,000 psi. What is this value in MPa?
- 827 MPa (Correct answer)
- 174 MPa
- 1034 MPa
- 689 MPa
Correct answer: 827 MPa
1 psi = 0.006895 MPa, so 120,000 psi × 0.006895 = 827.4 MPa.
Question 4: An M10 bolt has a pitch of 1.5 mm. What is the approximate threads per inch (TPI) equivalent?
- 16.9 TPI (Correct answer)
- 15.0 TPI
- 25.4 TPI
- 10.0 TPI
Correct answer: 16.9 TPI
TPI = 25.4 ÷ pitch (mm), so 25.4 ÷ 1.5 = 16.93 TPI.
Question 5: Convert 50 inch-pounds (in·lbf) of torque to Newton-meters (N·m).
- 5.65 N·m (Correct answer)
- 4.43 N·m
- 8.47 N·m
- 11.30 N·m
Correct answer: 5.65 N·m
1 in·lbf = 0.1130 N·m, so 50 × 0.1130 = 5.65 N·m.
Question 6: A washer has an outer diameter of 1.500 inches. What is this dimension in millimeters?
- 38.10 mm (Correct answer)
- 25.40 mm
- 50.80 mm
- 30.48 mm
Correct answer: 38.10 mm
1 inch = 25.4 mm, so 1.500 × 25.4 = 38.10 mm.
Question 7: A metric fastener drawing specifies a hole depth of 25 mm. A technician measures 1.00 inch. Is the hole deep enough?
- No; 1.00 inch = 25.4 mm, which exceeds 25 mm
- Yes; 1.00 inch = 25.4 mm, which exceeds 25 mm (Correct answer)
- No; 1.00 inch = 24.5 mm, which is less than 25 mm
- Yes; 1.00 inch = 25.0 mm exactly
Correct answer: Yes; 1.00 inch = 25.4 mm, which exceeds 25 mm
1.00 inch = 25.4 mm, which is greater than the required 25 mm, so the hole is deep enough.
CFS Metric & Imperial Conversion 2
A bolt has a shank diameter of 12 mm.
What is the closest standard inch fractional size?