Millwright Interview Questions
& Model Answers, 2026

Lock out and verify zero energy, inspect and clean the feet and shims, check and correct soft foot, take rough alignment, then measure with dial indicators or a laser system in both vertical and horizontal planes, correct vertical first with calibrated shims, then horizontal with jacking bolts, and re-measure until inside the tolerance for the speed and coupling type. Record the before and after readings, torque the bolts and re-check, and account for thermal growth on hot machines. Skipping soft foot means you will chase the alignment all day.

Soft foot is a condition where a machine foot does not sit flat on its shim pack, so tightening it distorts the frame and moves the shaft. Find it by placing an indicator on the shaft or the foot and loosening each bolt one at a time to see how much movement occurs. Correct parallel soft foot with shims, angular soft foot by machining or by tapered shims, and correct induced soft foot by fixing the pipe strain or the bent foot that is causing it. Shimming an angular soft foot flat is a common wrong answer.

Offset or parallel misalignment means the shaft centrelines are parallel but displaced; angular means they meet at an angle. Both load the coupling and the bearings, but they produce different vibration signatures — offset typically shows strongly at twice running speed radially, angular shows axially. A real alignment usually contains both, in both planes, which is why you correct four values, not one. Knowing the vibration signatures shows you can verify your own work.

Confirm the shaft and housing fits with a micrometre against the specification, clean everything, and mount by heating the inner ring with an induction heater to the specified temperature rather than driving it, or press on the ring that has the interference fit, never through the rolling elements. Never hammer directly, never heat with a torch, and keep dirt out. Damage shows as brinelling from impact loads passed through the balls, or as a spun race from an undersized fit.

Clean and chip the foundation to sound concrete, set anchor bolts with proper sleeves, level the baseplate with jack screws to the required tolerance across the mounting surfaces, confirm the surfaces are flat and coplanar, then place epoxy grout with proper venting so no voids form under the plate, and allow the cure time before torquing the anchors and doing a final alignment. A void or an unlevel plate guarantees soft foot and alignment that never holds.

Backlash and tooth contact pattern against specification, bearing clearances and end float, shaft runout, seal and gasket condition and correct seal orientation, the breather, and the oil type and level. Inspect the old gear tooth wear pattern for what it says about previous alignment or loading. After installation, align the gearbox to the driver and driven machine and record the readings. Reassembling without checking the contact pattern is how a rebuilt box fails in a month.

The instructive causes are pipe strain pulling a pump off, thermal growth not accounted for on a hot machine, a cracked or voided grout under a baseplate, or a soft foot corrected with the wrong shim geometry. Describe how you proved the cause rather than shimming repeatedly, and what the permanent correction was. Every maintenance manager has a machine like this and is listening for someone who could fix it.

Strong answers show planning: rigging plans and lifting gear staged in advance, parts kitted and verified before the outage, sequencing so alignment is not left until the last hour, and honest early reporting when a task was slipping. Add how you handed over to the next shift so work continued. Being on the critical path and silent about a delay is what interviewers are screening out.

Describe the actual thinking: the load weight and centre of gravity, sling angles and the resulting tension, the rated capacity of every component in the system, the lift path and exclusion zone, tag lines, and who was the designated signaller. Say that you would stop a lift when the plan and the reality diverged. Millwrights who describe eyeballing a lift are a serious liability.

Precision work needs the machine cold, clean, isolated and yours for a known window, and production always wants it back sooner. Describe negotiating a realistic window, explaining what a rushed alignment costs in bearing life, and making the trade-off visible rather than accepting an impossible window and doing a rough job.

Anchor on published data: the BLS OEWS May 2025 national median for millwrights is $65,700 a year ($31.59/hr), with the top 10% above $93,600. Place yourself with specifics — laser alignment competence, gearbox and turbine work, rigging tickets, and whether you can be trusted on a critical-path shutdown task unsupervised. In-plant maintenance roles and travelling shutdown work often price very differently, so say which you are quoting.

Significantly. Ask how many outages a year the site runs, the typical shift length and pattern during them, the overtime multiplier and whether double time applies past a threshold, whether hours are guaranteed for the outage duration, and how travel and per diem work if the site is away from home. A modest base with a heavy outage calendar can out-earn a higher base with none.

Employer-supplied precision tools — laser alignment system, induction heater, dial indicators and micrometres — because buying them personally is expensive, plus training on the alignment and vibration platforms the site uses, rigging and crane certification renewal, boot and FR clothing allowance, and a defined step to lead millwright or planner. Confirm who pays for site-specific safety training and badging.