CFS Study Guide 2026
Everything you need to pass the CFS exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 CFS Exam Format at a Glance
📚 CFS Topics to Study (69)
✍️ Sample CFS Questions & Answers
1. Which standard defines the unified inch screw thread series (UN, UNC, UNF) used in the United States?
ASME B1.1 defines the Unified Inch Screw Thread standard, covering UN, UNC, UNF, UNEF, and other unified thread series used in US practice.
2. Which ASME standard governs the dimensional requirements for hex cap screws used in pressure vessels?
ASME B18.2.1 specifies dimensional requirements for inch series square and hex bolts and screws, including hex cap screws.
3. What does the 'k factor' (nut factor) represent in the torque-tension equation T = k × F × d?
The nut factor k ≈ 0.1–0.2 for typical lubricated bolts is an empirical constant that lumps thread friction, under-head friction, and geometry into a single multiplier.
4. NADCAP (National Aerospace and Defense Contractors Accreditation Program) accreditation for fastener manufacturers most commonly covers which special process?
NADCAP accreditation for fastener suppliers most commonly covers heat treatment as it is a critical process affecting mechanical properties.
5. When using the torque-angle method, what is measured after reaching a threshold torque?
After a snug or threshold torque is reached, additional rotation (angle) stretches the bolt a predictable amount into the target clamp load range.
6. Which of the following best describes the locking mechanism of a prevailing torque nut (e.g., nylon insert lock nut)?
Prevailing torque nuts create a mechanical interference fit — through a nylon insert or deformed metal threads — that resists rotation independent of the joint's clamp load.