These are five sample questions from Bryq’s CNC Operator assessment, a job-specific test for hiring CNC operators, machinists, and setup technicians. The full assessment covers five skills: CNC machinery operation, precision measurement tools, mechanical document interpretation, math skills, and safety compliance. Questions combine machining knowledge and shop-floor calculations with practical setup and safety scenarios, each with four options to choose from.
CNC Machinery Operation Knowledge
Question
After a tool change, the first part’s pocket is cut 0.5 mm deeper than programmed, although the previous tool cut to depth correctly. What is the most likely cause?
Select your answer
The new tool’s length offset was set or entered incorrectly.
The feed rate is too high for the material.
The spindle speed is too low for the tool.
The work coordinate Z zero has shifted.
WHY IS THIS THE CORECT ANSWER
A depth error that appears only with the new tool points to that tool’s length offset. The work zero is shared by every tool, and the previous tool cut correctly, so the zero hasn’t shifted. Feed and speed affect finish and tool life, not programmed depth.
Precision Measurement Tools
Question
You need to inspect a bore specified at Ø25.000 mm ± 0.010 mm. Which tool gives the most reliable reading?
Select your answer
Three-point bore micrometer.
Dial indicator on a magnetic base.
Digital caliper, using the inside jaws.
Telescoping gauge, read against a steel rule.
WHY IS THIS THE CORECT ANSWER
A ±0.010 mm tolerance calls for an instrument far more precise than the tolerance band. A three-point bore micrometer centers itself in the bore and reads to 0.001 mm. A caliper’s accuracy is too coarse, and a dial indicator measures variation rather than diameter.
Mechanical Document Interpretation
Question
A hole callout on a drawing reads “Ø10 H7”. What does “H7” specify?
Select your answer
A tolerance class that defines the hole’s allowable size range.
A hole depth of 7 mm.
A finishing operation using a grade 7 reamer.
A surface roughness of 7 µm.
WHY IS THIS THE CORECT ANSWER
H7 is an ISO fit designation. “H” places the lower limit at the nominal size, and “7” is the tolerance grade that sets the width of the band. For a Ø10 hole, H7 allows 10.000 to 10.015 mm, a common fit for dowel holes and other precision fits.
Math Skills
Question
A part needs 0.120 inches of material removed, and each pass can be no deeper than 0.025 inches. What is the minimum number of passes?
Select your answer
5
3
4
6
WHY IS THIS THE CORECT ANSWER
Dividing 0.120 by 0.025 gives 4.8, so four passes would leave material behind. Passes always round up to the next whole number, giving five passes, each slightly shallower than the 0.025-inch maximum.
Safety Compliance
Question
During a production run, chips are building up around the vise and starting to wrap around the tool. What should you do?
Select your answer
Use feed hold, wait for the spindle to stop, then clear the chips with a hook or brush.
Increase the coolant flow to flush the chips away while the cycle runs.
Open the door and brush the chips away while the spindle turns slowly.
Let the cycle finish, then clear the chips before starting the next part.
