To train the trainer in manufacturing, start with what your best operator can’t say. Most train-the-trainer programs teach presentation skills. The real gap is that the expert doesn’t know what they know.
Hector Set the Gauge by Sound
Hector is the best operator on second shift, so the plant gave him the new hire. Three days later she still wouldn’t touch the press brake.
Someone asked why he sets the back gauge a hair short on thin stock. “It just sounds right,” he said.
He wasn’t being difficult. He was answering honestly. After enough years the steps disappear into the hands, and nobody can teach a step they can no longer see.
Why Is Your Best Operator a Poor Trainer?
Because expertise stops being conscious. The better the operator, the less they can explain.
A 2012 article in Production Machining by Miles Free of the Precision Machined Products Association, titled “Why Your Expert is Your Worst Trainer,” says the same thing from the shop floor. Asked how they reached a decision, he writes, experts typically answer “Because,” or “I just knew.” The article contains no data. It rests on the author’s own years as a plant manager and technician, and I’m citing it for the observation, not for a number.
In my experience, that observation holds. The steps a new hire needs most are the ones the trainer stopped noticing years ago.
This Isn’t a Hector Problem
It’s the same pattern in every plant that trains new people next to the experts. On a simple job, a trainer’s blind spots cost a few mistakes. On a hard job, they cost much more.
McKinsey makes the point in a 2025 article on investing in the manufacturing workforce. It states that productivity gaps between high and low performers “increase by as much as 800 percent as a task increases in complexity,” and attributes the figure to its own earlier talent survey, from 2017. The page gives no sample size, so treat it as a direction, not a forecast for your line.
Read that gap the other way, though. If the best operator is that far ahead on complex work, then the new hire is learning from the person with the most to teach and the least ability to say it. That’s slow onboarding with a respectable cause. We covered the speed side of it in how to train new operators faster.
What Does Train the Trainer in Manufacturing Usually Leave Out?
It leaves out the content. Most courses teach the trainer how to present, pace a session and give feedback. They don’t help the trainer find the things they do without thinking.
That’s the market in one line: courses about delivery, modules in a learning system, slide decks of generic technique. All useful. None of it extracts the key point Hector’s ear is catching. A trainer with perfect delivery and no words for the job still sends the new hire back to the machine to guess.
What Did Training Within Industry Get Right About Key Points?
It built the whole method around them. The War Manpower Commission’s 1945 report on Training Within Industry describes Job Instruction’s second step as explaining the operation: tell, show and illustrate one step at a time, and stress each key point. The report traces the “key points” idea to a study of lens-grinding work, where experienced workers broke a job into segments and identified the details that made an operation succeed. The Job Instruction card carries it forward: “Stress each KEY POINT.”
A key point is the detail that makes or breaks the step. It’s what Hector’s ear was catching. The idea is more than 80 years old, and most plants I know have the trainer carry it in their head. That’s the part worth fixing.
How to Train the Trainer in Manufacturing: Four Steps
Here’s the sequence I’d use. It’s my own practice, not a published standard.
- Pick one job and its best operator. Choose a job where new hires stall, not the easiest one.
- Capture the job from the doing, not the telling. Watch a full cycle. Stop at every adjustment and ask, “What are you noticing?” Write the answer in the operator’s words.
- Turn each “feel” into something a new person can check. “It sounds right” becomes “the gauge sits about the thickness of one coin short of the line.” Hector, not the writer, signs off on every one.
- Give the trainer the page, then step back. Teach from the key-point sheet, not from memory, and update the sheet when the trainer finds a new one.
The test of any trainer is simple. Can a person who has never run the job do it from the page, with the trainer silent? Our operator competency assessment piece shows how to check that, and our article on how to document tribal knowledge in a plant covers the capture side in more depth.
How We Upskill the Trainer
At SenseiLab, the person we train is the supervisor who owns the line. That supervisor leads the capture with the expert, validates the key points, and then coaches from them. The Sprint trains one internal champion so the work doesn’t depend on us once we leave.
The result is a trainer who can say what the expert does. Hector keeps his ear. The new hire gets the words.
Run the Trainer Test This Week
You don’t need us for this.
- Sit in on one training session. Don’t coach.
- Keep a tally of every “just,” “you’ll feel it,” “you’ll get it,” and “it sounds right.”
- After the session, ask the trainer about each tally mark: “What exactly are you noticing?”
- Write each answer as one sentence a new person could check.
- Hand those sentences to the trainer before the next hire starts.
Expect several tally marks in a single session. Each one is a key point that’s currently reaching new hires by luck.
Frequently Asked Questions About Train the Trainer in Manufacturing
What is train the trainer in manufacturing?
Train the trainer in manufacturing is preparing experienced operators or supervisors to teach a job to others. The version that works also helps the trainer put into words the details they do without thinking.
Why is my best operator a bad trainer?
Skill becomes automatic, so experts often can’t describe the steps behind their decisions. A 2012 Production Machiningarticle describes experts answering “Because” or “I just knew.” The fix is capturing the job from watching and questioning, not from asking them to explain.
How do we train new operators faster?
Start with the trainer. Capture the key points of the job in the expert’s words, teach from that page, and test whether a new person can run the job from it. Our article on how to train new operators faster covers the rest of the method.
What are key points in job instruction?
Key points are the details that make or break a step: what to watch for, a specific setting, a point of safety. Training Within Industry made them a core part of Job Instruction in the 1940s.
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About the author: Diego Echenique, MBA, is CEO & co-founder of SenseiLab, with 20+ years in manufacturing operations.
