Assembly is a skilled trade, not just fitting: a fix for machinery makers

In a pump maker's assembly bay, two fitters build the same model. One clocks shaft runout with a dial gauge before fitting the mechanical seal. He sets impeller clearance with feelers and spins the rotor by hand before closing the casing. The other bolts it up to the drawing and wheels it to the test bench. Both are listed as fitter. Both draw the same wage. Only one is practising the trade.

The machinery and equipment builders' page lists this among its recurring strains. A builder that files assemblers under general labour pays for it later, on the bench and at the customer's site.

• Reads GA and detail drawings, and spots a dimension that cannot be right before parts go together.
• Corrects small misfits by reaming a dowel hole, adding a shim pack or easing a keyway, then notes what he did.
• Sets what the drawing only specifies: bearing preload, gear backlash, chain tension and coupling alignment.
• Tests as he goes with a dial gauge, feelers, a spirit level and a torque wrench, rather than leaving it all to the final trial.
• Knows when to down tools and ring the designer rather than force a part that should not fit.

• Sub-assemblies come back from the bench with noise, heat or leaks that a careful fitter would have caught.
• Punch lists at factory acceptance run long with small mechanical items.
• Complaints arrive weeks after dispatch: a loose locknut, a seal run dry, a coupling out of line.
• The same two seniors get pulled onto every difficult machine, and their own builds slip.
• Good assemblers drift to builders who grade them properly, and replacements take a year to settle.

Rework on a machine already built is the dearest kind. Stripping a gearbox to reset backlash eats a day nobody planned. A misalignment found at the customer's plant means a service trip and a strained relationship. These costs rarely sit under one heading. They hide in overtime, travel claims and late dispatch.

Attrition adds its own share. Each experienced fitter who leaves takes years of feel in his hands. Special purpose builders suffer most, because no two machines repeat and every build leans on judgement.

• Hiring on the certificate alone. A trade certificate shows someone trained. It says nothing about building a gearbox.
• One title for everyone. Helper, fitter and senior fitter blur into a single word on the attendance sheet.
• Pay fixed at joining and moved by years. Skill gained afterwards barely registers.
• Testing belongs to someone else. Where the bench is the only check, fitters stop checking as they build.
• Seniors are judged on their own output. Teaching a helper slows them down, so they skip it.

• List every assembler by name, with the sub-assemblies each can build and test without help.
• Lay that list beside current grades and pay, and mark where they disagree.
• Pull the bench rework log for recent months and tag each fault to an assembly step.
• Ask the senior fitters which jobs they never hand to anyone else, and why.

1. 1

   Describe the trade in levels

   Helper, guided fitter, fitter who builds a sub-assembly alone, senior who builds and tests a whole machine, and lead who trains others. Define each by what the person can build and check unaided.

2. 2

   Write a sign-off card per level

   List the tasks: set bearing preload, align a coupling with two dial gauges, set backlash, torque a flange in sequence. A senior fitter watches each task done alone and signs.

3. 3

   Tie pay to the level, not the calendar

   Each level carries a pay band, published on the floor. A fitter moves up when his card is complete, not when another year ends.

4. 4

   Build testing into assembly

   Each sub-assembly gets a short check sheet the fitter fills before handing it on. The bench then confirms quality instead of discovering faults.

5. 5

   Pay seniors for teaching

   Make training a helper part of the senior fitter's level and review, and give the pair time on the build plan.

6. 6

   Test before hiring

   Add a practical test to recruitment: a small sub-assembly, a deliberate misfit to correct and a drawing to read aloud.

A ladder decays once sign-offs become a formality. Rotate the witnessing senior, and have the works manager audit a few cards each quarter. Twice a year, set the rework log against the ladder; faults should fall as levels rise. Rewards design can shape the bands so they hold against outside offers.

Machine tool builders push this furthest, with scraping and alignment that take years, as their scraping and alignment ladder shows. Pump makers meet the same gap on seals and clearances, which a pay comparison for pump shops addresses. To put each level into words, see defining the skill in a job description.