Engineering trades: machining, welding and fitting

The families and how they differ

Engineering production rests on several crafts that sit alongside one another but do not substitute. The difference is not a level of dexterity but what they work with: a machinist removes material, a welder joins it, a fitter assembles and fits, a toolmaker makes and maintains the tooling with which everything else is then made. Where a brief merges these roles into one, the selection process is looking for someone who is either not on the market at all or is overqualified for the work.

The list below serves as a shared vocabulary for a conversation between production and the personnel department. A detailed description of the work activities and professional requirements for each of these trades is maintained by the Czech national occupations register.

The families that recur in engineering production:

• Metal machinist — turning, milling and drilling on conventional and CNC machines, with the emphasis on dimension and tolerance
• CNC operator and setter — operating the machine and preparing it for an order; the line between the two is decisive for recruitment
• Welder — joining material by method and position; the scope of the qualification is given by the tested range stated in the certificate
• Fitter — assembly, fitting, and the repair and maintenance of structures and machine assemblies
• Toolmaker — making and maintaining moulds, fixtures and blanking tools, with high demands on precision and repeatability
• Grinder — finishing operations, where surface roughness and the final dimension are decided
• Assembler and mechanic — assembly, commissioning and service of machines, both in-house and at a customer’s site

Operating, setting and programming are not the same

The most common mistake in a brief concerns the level rather than the trade. An operator watches the machine, loads and unloads parts, checks dimensions and handles routine situations. A setter prepares the machine for a different order — clamps the fixture, measures tools, sets the zero point, adjusts offsets and cuts the first part. A programmer creates the technology and the tool path, whether by shop-floor programming directly at the machine or in a CAM system.

Each of these levels has a different availability on the market and a different time to competence. A company that puts all three into a single advertisement usually gets applications from operators while it is waiting for a setter. The difference, and what follows from it for fillability, is covered by a separate page on recruiting CNC operators and setters.

Drawings and gauges are the real dividing line

Two areas of questioning yield the most in selection: what the candidate reads from a drawing, and what they do with a gauge. Reading a drawing does not mean finding a dimension. It means understanding the tolerance band, geometric tolerances, specified surface roughness, sections and views, and welding symbols — that is, what happens when the dimension is right and the form is not.

The second area is metrological. Callipers, a micrometer, a dial indicator and limit gauges are used differently and measure to different accuracies; an experienced worker knows when a given instrument is not enough and when measurement on a coordinate measuring machine is called for. Order in the calibration of gauges belongs on the same level: the general framework for measuring instruments and their traceability comes from the Czech act on metrology, while the regime for working gauges is set by the operation in its own metrological rules — and customer audits ask about it.

What to put to a candidate:

• Have them read a real drawing from your own production, not a generic exercise
• Ask how they would measure a particular dimension, and why with that instrument
• Ask about a situation where a part did not conform — what they did and whom they informed
• Check whether they worked to a control plan and how they recorded the results

One machine, several machines, and moving between sectors

The second axis is breadth. A worker settled on one type of machine in long-run production has a different profile from one who moves between machines in one-off and small-batch work, reads the drawing themselves and sets up themselves.

Multi-machine working is not only a question of skill but of workplace layout and machining times; without those it cannot be expected even after training.

Experience from another sector transfers unevenly. The craft base — measuring, reading a drawing, clamping, working with tooling — transfers well. What transfers less well is anything tied to the material, the batch size and the documentation: someone who machined aluminium castings in automotive series production is not immediately at home in one-off stainless steel work, and the reverse holds too. In welding the line is harder, because the scope of the qualification is set by the tested range stated in the certificate, not by length of practice.

Describing the trade: the national registers as a shared vocabulary

For describing a position it pays not to invent your own terminology. The Czech national occupations register describes occupations, typical positions and their professional requirements; the Czech national qualifications register assigns professional qualifications with an assessment standard, which can be evidenced by a certificate after an examination before an authorised person under the Czech act on verification and recognition of further education. For an employer this is practical twice over: the brief takes an intelligible shape, and at the same time a route opens to candidates who know the trade but do not hold the corresponding apprenticeship certificate.

Alongside these there are documents that nothing else can replace. For welding it is the welder qualification certificate to the relevant standard with its stated tested range; for work on electrical equipment, proof of electrotechnical competence; for reserved technical equipment, the corresponding certificate. These documents have limited validity and belong in the brief right at the start, not at the signing of the contract.

How to write the trade into a brief:

• Name the trade as the national occupations register names it, not by an internal abbreviation or a cost-centre number
• Distinguish the level: operating, independent work to a drawing, or setting
• List the machines, the materials machined and the typical batch size
• Describe the shift pattern and the workplace before you get to pay
• List the mandatory documents, including their scope and the validity required