CPI Fasteners, Anchors & Hardware 1 — Questions and Answers
Question 1: Which type of anchor is best suited for securing heavy equipment to hollow concrete block (CMU) walls?
- Sleeve anchor
- Toggle bolt (Correct answer)
- Hollow wall anchor
- Wedge anchor
Correct answer: Toggle bolt
Toggle bolts distribute load across a wide area behind the hollow wall, making them suitable for CMU or hollow block applications where solid embedment is not possible.
Question 2: What does the term 'shear load' refer to when selecting a fastener?
- The pulling force parallel to the fastener axis
- The force acting perpendicular to the fastener axis (Correct answer)
- The torque applied during installation
- The maximum tensile strength of the bolt
Correct answer: The force acting perpendicular to the fastener axis
Shear load is a force acting perpendicular (sideways) to the fastener's axis, as opposed to tensile (pull-out) load which acts along the axis.
Question 3: A Class 8.8 metric bolt indicates which property?
- The bolt diameter in millimeters is 8.8
- Minimum tensile strength of 800 MPa and yield strength of 640 MPa (Correct answer)
- It is rated for 8 tons at 8% elongation
- The bolt has 8 threads per 8mm of length
Correct answer: Minimum tensile strength of 800 MPa and yield strength of 640 MPa
The Class 8.8 designation means the bolt has a minimum tensile strength of 800 MPa and a yield-to-tensile ratio of 0.8, giving a yield strength of 640 MPa.
Question 4: When installing a wedge anchor into concrete, what is the minimum edge distance typically required?
- 1 times the anchor diameter
- 2.5 times the anchor diameter
- 5 times the anchor diameter (Correct answer)
- 10 times the anchor diameter
Correct answer: 5 times the anchor diameter
Most wedge anchor manufacturers specify a minimum edge distance of at least 5 anchor diameters to prevent concrete edge blowout and maintain rated load capacity.
Question 5: What is the primary advantage of using stainless steel fasteners over zinc-plated steel fasteners in exterior installations?
- Stainless steel is harder and resists stripping
- Stainless steel offers superior corrosion resistance in wet or coastal environments (Correct answer)
- Stainless steel fasteners are less expensive
- Stainless steel provides greater tensile strength
Correct answer: Stainless steel offers superior corrosion resistance in wet or coastal environments
Stainless steel fasteners resist oxidation and corrosion far better than zinc-plated steel, making them the preferred choice for exterior, marine, or high-humidity environments.
Question 6: Which fastener drive type provides the best resistance to cam-out during high-torque installation?
- Phillips (cross-head)
- Slotted (flat-head)
- Torx (star-drive) (Correct answer)
- Pozidriv
Correct answer: Torx (star-drive)
Torx (star-drive) fasteners have a six-point star pattern that virtually eliminates cam-out, allowing high torque to be applied without the driver slipping out of the head.
Question 7: For a lag screw installation, the pilot hole in the member being fastened should be drilled to what size?
- The full shank diameter of the lag screw (Correct answer)
- 75–90% of the shank diameter
- 50% of the shank diameter
- No pilot hole is needed for lag screws
Correct answer: The full shank diameter of the lag screw
The pilot hole through the first (clamped) member should match the full shank diameter of the lag screw so the threads grip only in the receiving member.
CPI Fasteners, Anchors & Hardware 1
Which type of anchor is best suited for securing heavy equipment to hollow concrete block (CMU) walls?