CFS Torque & Tension Specifications 2

Question 1

What is the primary purpose of applying torque to a fastener?

Accepted Answer

To develop clamp load (tension) in the joint

Answer

Torque is the input; the goal is to generate clamp load (tension) that keeps the joint together.

Question 2

Approximately what percentage of applied torque is typically consumed by friction under the bolt head or nut face?

Accepted Answer

50%

Answer

Roughly 50% of torque is lost to bearing-surface friction, 40% to thread friction, and only about 10% creates bolt tension.

Question 3

Which fastener property most directly determines the relationship between torque and clamp load?

Accepted Answer

Nut factor (K)

Answer

The nut factor K encapsulates friction and geometry effects, making T = K × D × F the standard torque formula.

Question 4

A grade 8 bolt and a grade 5 bolt of the same size are torqued to the same value. Which statement is correct?

Accepted Answer

The grade 8 develops higher clamp load due to higher yield strength

Answer

Higher-grade bolts have higher proof strength, so the same torque keeps them below yield while stretching them more elastically to develop greater tension.

Question 5

What does 'torque-to-yield' (TTY) installation mean?

Accepted Answer

Intentionally stretching the bolt beyond its elastic limit for higher clamp load

Answer

TTY fasteners are deliberately torqued past the elastic range to achieve consistent, high clamp load; they must be replaced after disassembly.

(CFS) Certified Fastener Specialist Practice Test

(CFS) Certified Fastener Specialist Practice Test

CFS Torque & Tension Specifications 2