CFS CFS Fastener Head Styles & Drive Types 2

Question 1

What is the primary advantage of a hex flange head fastener over a standard hex head fastener?

Accepted Answer

Integrated flange acts as a built-in washer, distributing load and reducing the need for a separate washer

Answer

The flange on a hex flange head extends radially from the hex body, providing a larger bearing surface that distributes clamping load and often eliminates the need for a separate flat washer.

Question 2

Which drive type offers the highest torque transfer capability and best resistance to cam-out among common drive styles?

Accepted Answer

Torx (6-lobe)

Answer

Torx (6-lobe) drives engage the fastener walls with vertical flanks rather than angled ones, enabling higher torque transfer and virtually eliminating cam-out compared to slotted or Phillips drives.

Question 3

A 'Pozidriv' drive is most accurately described as:

Accepted Answer

An improved Phillips drive with additional ribs between the four main wings to reduce cam-out

Answer

Pozidriv is an evolution of the Phillips drive that adds four secondary radial ribs at 45° to the main wings, significantly reducing cam-out and improving torque transfer.

Question 4

Which of the following head styles is most commonly specified for structural steel bolted connections per AISC and RCSC standards?

Accepted Answer

Heavy hex head

Answer

Heavy hex head bolts have larger head dimensions than standard hex heads, providing greater bearing area and wrench engagement required for high-strength structural bolting per AISC/RCSC specifications.

Question 5

What is the purpose of a 'tamper-resistant' or 'security' drive, such as a pin-in-Torx or one-way slotted fastener?

Accepted Answer

To prevent unauthorized removal using standard tools

Answer

Tamper-resistant drives require special tools for removal, deterring unauthorized disassembly in public fixtures, electronics, and security-sensitive installations.

(CFS) Certified Fastener Specialist Practice Test

(CFS) Certified Fastener Specialist Practice Test

CFS CFS Fastener Head Styles & Drive Types 2