NCCER CORE Power Tool Safety and Operation Questions and Answers 1 — Questions and Answers
Question 1: A worker is operating a bench grinder to sharpen a chisel. According to OSHA standards, what is the maximum allowable gap between the work rest and the face of the grinding wheel?
- 1/2 inch
- 1/4 inch
- 1/8 inch (Correct answer)
- 3/4 inch
Correct answer: 1/8 inch
OSHA standard 1910.215 requires that the work rest on a bench grinder be kept adjusted closely to the wheel with a maximum opening of 1/8 inch. This is to prevent the workpiece from being jammed between the wheel and the rest, which could cause wheel breakage and injury.
Question 2: When operating a pneumatic nailer, which of the following actions is a critical safety practice that must be performed before attempting to clear a jam or perform any maintenance?
- Engage the trigger lock
- Increase the air pressure slightly
- Point the tool towards the ground
- Disconnect the tool from the air supply (Correct answer)
Correct answer: Disconnect the tool from the air supply
Before performing any service, such as clearing a jam or changing accessories on a pneumatic tool, the user must first disconnect it from the air supply. This prevents accidental actuation of the tool, which could cause serious injury.
Question 3: Which of the following is an unsafe practice when using an electric power tool with a cord?
- Using a Ground Fault Circuit Interrupter (GFCI) protected outlet
- Carrying the tool by its cord (Correct answer)
- Inspecting the cord for damage before each use
- Ensuring the power switch is 'OFF' before plugging it in
Correct answer: Carrying the tool by its cord
Never carry a power tool by its cord. This can put stress on the cord and its connection to the tool, potentially damaging the wiring and creating an electrical hazard. Always carry the tool by its handle.
Question 4: A construction worker is preparing to use a powder-actuated tool to fasten a steel track to a concrete wall. What is a fundamental safety rule specific to operating this type of tool?
- The tool should only be loaded after it is pressed against the work surface.
- A low-velocity charge should be tested first, even if a high-velocity charge is needed.
- The tool must be held firmly against the work surface and perpendicular to it. (Correct answer)
- Hearing protection is optional if working in an open, well-ventilated area.
Correct answer: The tool must be held firmly against the work surface and perpendicular to it.
Powder-actuated tools must be held firmly against and perpendicular to the work surface. This ensures the fastener drives straight into the material and minimizes the risk of ricochet or the fastener passing completely through the material.
Question 5: A worker is using a circular saw to cut plywood. The blade guard is wedged open and does not spring back to cover the blade after a cut. What is the correct course of action?
- Continue using the saw carefully for the rest of the day and report it later.
- Attempt to repair the spring mechanism on-site with available materials.
- Remove the saw from service immediately and tag it as 'Do Not Use'. (Correct answer)
- Ask a coworker to watch the blade and provide a verbal warning.
Correct answer: Remove the saw from service immediately and tag it as 'Do Not Use'.
If any safety guard on a power tool is damaged or not functioning correctly, the tool must be removed from service immediately. A tag indicating that the tool is unsafe should be attached to prevent others from using it until it is properly repaired by a qualified person.
Question 6: To protect against electric shock, which safety device is required by OSHA when using portable electric tools on a construction site, especially in damp or wet locations?
- A surge protector
- A trigger lock
- A heavy-duty extension cord
- A Ground-Fault Circuit Interrupter (GFCI) (Correct answer)
Correct answer: A Ground-Fault Circuit Interrupter (GFCI)
OSHA requires the use of a Ground-Fault Circuit Interrupter (GFCI) for all 120-volt, single-phase, 15- and 20-ampere receptacle outlets on construction sites that are not part of the permanent wiring of the building. GFCIs are crucial for preventing electrocution by detecting ground faults and quickly shutting off power.
NCCER CORE Power Tool Safety and Operation Questions and Answers 1
A worker is operating a bench grinder to sharpen a chisel.
According to OSHA standards, what is the maximum allowable gap between the work rest and the face of the grinding wheel?