SC QUALITY GUILDCertified Quality Inspector (CQI)
The entry point to the technical track. Measurement, drawing interpretation, inspection method and the judgment to know when a reading cannot be trusted.
The paper carries 110 questions in total: 100 that are scored and 10 unscored pretest items that do not count toward your result.
The Quality Inspector Primer is published, in two volumes. Volume 1 works the CQI Body of Knowledge section by section. Volume 2 is practice and worked solutions.
What the CQI examination covers
The Body of Knowledge divides into 4 sections. The question count is what each section is worth on the paper, which is not the same as how long it takes to learn.
| Section | Topic | Questions |
|---|---|---|
| I | Technical Mathematics | 19 |
| II | Metrology | 26 |
| III | Inspection and Test | 32 |
| IV | Quality Assurance and Improvement | 23 |
Section by section
I — Technical Mathematics
The mathematics an inspector uses daily — tolerances, conversions, ratios and geometry — taught on real drawing values rather than abstract exercises.
II — Metrology
Metrology: instrument selection, resolution against tolerance, cosine error, and the difference between an instrument that displays precision and one that has it.
III — Inspection and Test
Inspection and test methods, first article, sampling and what to do with a reading that sits inside measurement uncertainty. That decision belongs to the documented disposition process, not to the bench.
IV — Quality Assurance and Improvement
Quality assurance concepts, documentation and the inspector's contribution to prevention. A trend inside specification is information about the process, and reporting it is the difference between detection and prevention.
Questions from the free practice test
Every item carries the reasoning, not just the answer, and none of them appears in any book. The CQI self-assessment covers every requirement in the Body of Knowledge: choose a 20-question random sample, a quick check at half the exam's length, a full exam at its real length and section mix, or work on your weak spots.
A dimension of 2.375 inches converted to millimeters is approximately:
- 60.33 mm
- 59.05 mm
- 58.10 mm
- 62.50 mm
One inch is 25.4 mm exactly, so 2.375 x 25.4 = 60.325. Rounding to the resolution of the measurement rather than to the precision of the calculator is what keeps the figure honest.
A micrometer reading to 0.0001 in is appropriate for a tolerance of:
- 0.00005 in
- 0.0002 in
- 0.0001 in
- 0.002 in
The ten-to-one convention asks for resolution around a tenth of the tolerance. On a 0.002 in tolerance a 0.0001 in instrument discriminates twenty levels, which is comfortable; on 0.0002 in it discriminates two.
Datums in a feature control frame are listed:
- By size
- By location
- Alphabetically
- In order of precedence
The order establishes how the part is constrained: primary contacts first and removes the most degrees of freedom. Reversing them changes how the part sits and therefore the measured result.
The practice test is free and needs no account. The CQI test is a full self-assessment covering all 93 requirements in the current Body of Knowledge, with the reasoning on every answer, a score for every requirement and your progress over time. Or work through the primer week by week in the free six-week self study, with a check after every reading.