Mixed Deck — All CFS Topics Flashcards

Which standard defines the unified inch screw thread series (UN, UNC, UNF) used in the United States?

Answer: ASME B1.1

ASME B1.1 defines the Unified Inch Screw Thread standard, covering UN, UNC, UNF, UNEF, and other unified thread series used in US practice.

Which ASME standard governs the dimensional requirements for hex cap screws used in pressure vessels?

Answer: ASME B18.2.1

ASME B18.2.1 specifies dimensional requirements for inch series square and hex bolts and screws, including hex cap screws.

What does the 'k factor' (nut factor) represent in the torque-tension equation T = k × F × d?

Answer: An empirical coefficient combining all frictional and geometric effects

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.

NADCAP (National Aerospace and Defense Contractors Accreditation Program) accreditation for fastener manufacturers most commonly covers which special process?

Answer: Heat treatment

NADCAP accreditation for fastener suppliers most commonly covers heat treatment as it is a critical process affecting mechanical properties.

When using the torque-angle method, what is measured after reaching a threshold torque?

Answer: Additional degrees of rotation beyond the threshold

After a snug or threshold torque is reached, additional rotation (angle) stretches the bolt a predictable amount into the target clamp load range.

Which of the following best describes the locking mechanism of a prevailing torque nut (e.g., nylon insert lock nut)?

Answer: It creates friction through a deformed or non-metallic insert that grips the bolt threads independent of clamping load

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.

For a bolted joint in a pressure vessel, the ASME Boiler & Pressure Vessel Code requires the bolt area to satisfy two loading conditions. What are they?

Answer: Gasket seating condition (no pressure) and operating condition (with pressure)

ASME BPVC requires bolts to satisfy both the gasket seating condition (cold, atmospheric) and the operating condition (hot, pressurized), with the governing (larger) bolt area used.

Which standard governs the qualification and approval of aerospace fastener manufacturers under the National Aerospace and Defense Contractors Accreditation Program?

Answer: NADCAP AC7102

NADCAP AC7102 is the audit criteria used to accredit fastener manufacturers supplying the aerospace and defense industry through the NADCAP program.

A fastener drawing uses the designation 'M16×2-6g.' What does the '2' represent?

Answer: The thread pitch in millimeters

In metric thread callouts, the number after the × symbol is the pitch in millimeters.

Which procurement strategy is most appropriate when a fastener is highly customized, sole-sourced, and critical to product function?

Answer: Strategic partnership with intensive supplier development investment

Critical, sole-sourced, highly customized fasteners warrant a strategic partnership where the buyer invests in supplier development to ensure long-term reliability and access.

Which incoterm places the maximum responsibility (cost and risk) on the seller for delivering fasteners to the buyer's named destination?

Answer: DDP (Delivered Duty Paid)

DDP (Delivered Duty Paid) requires the seller to handle all transportation, insurance, customs clearance, and duties until goods are delivered to the named destination.

A fastener's shear strength is listed as 90,000 psi. What is this in ksi?

Answer: 90 ksi

1 ksi = 1,000 psi, so 90,000 psi ÷ 1,000 = 90 ksi.

In a tension-critical structural connection (e.g., AISC), the design tension strength of a bolt is taken as a fraction of its ultimate tensile strength. What fraction does AISC LRFD use (φ)?

Answer: φ = 0.75

AISC LRFD uses a resistance factor φ = 0.75 for bolt tension, reflecting the greater variability and consequence of bolt tensile failure.

The 'proof load' of a fastener is best defined as:

Answer: The maximum load the fastener can withstand without permanent deformation

Proof load is the tensile force that a fastener must support without taking any permanent set (deformation), and it defines the upper limit for preload.

What is the primary purpose of applying anti-seize compound to a fastener before installation?

Answer: To prevent galling, corrosion, and seizure for easier future removal

Anti-seize compounds lubricate the threads and contact surfaces to prevent metal-to-metal seizure, corrosion bonding, and galling, enabling easier disassembly.

How should CFS professionals handle confidential information related to torque & tension specifications?

Answer: Follow established protocols for data protection, access control, and disclosure in accordance with applicable regulations

Confidential information must be handled according to established protocols, regulatory requirements, and professional ethics standards, including proper access control and disclosure procedures.

An anchor bolt is specified as 5/8-11 UNC. What is the nominal diameter in millimeters?

Answer: 15.875 mm

5/8 inch = 0.625 in × 25.4 = 15.875 mm.

What does the RoHS Directive restrict in fastener manufacturing?

Answer: Use of certain hazardous substances including lead and cadmium

The EU RoHS Directive restricts the use of specific hazardous substances such as lead, mercury, cadmium, and hexavalent chromium in electrical and electronic equipment, including fasteners used in such products.

What does the term 'lot traceability' mean in fastener quality control?

Answer: Tracking a fastener from raw material heat through finished product

Lot traceability links each finished fastener lot back to the raw material heat, manufacturing records, and test data for accountability.

Grade 5 fasteners electroplated with cadmium were historically popular in aerospace primarily because cadmium:

Answer: Provides excellent corrosion protection and is compatible with aluminum

Cadmium plating provides excellent corrosion resistance, low contact resistance, and is galvanically compatible with aluminum airframes, making it historically popular in aerospace.