26 May 2026
Choosing a precision engineering partner is rarely a like-for-like comparison. Two suppliers can both say they can make something, but deliver very different outcomes.
Most precision engineering vendors will tell you they’re accurate, reliable, and quality-focused. The trouble is, those words don’t tell you much until you know what’s actually behind them.
Whether you’re auditing a current supplier or onboarding a new one, these are the questions that tend to separate a genuinely capable partner from one that’s just confident on a website.
Almost every machine shop mentions “quality” somewhere in their marketing. Far fewer can produce certificates that prove it, and fewer still hold accreditations that matter for your specific sector.
For aerospace and defence work, AS9100 (or its European equivalent EN9100) is the benchmark, going well beyond ISO9001 in its requirements around traceability and risk management. ISO14001 demonstrates environmental management is built into the business, and ISO45001 covers health and safety standards.
If you’re in the UK defence supply chain, JOSCAR accreditation and Cyber Essentials certifications are also worth checking for, given the sensitivity of the data being shared.
Look out for: certificate numbers and renewal dates given without hesitation, and accreditation relevant to your sector specifically. Not just a generic ISO9001 badge.
A business that’s survived decades of changing standards and customer audits has had to keep adapting. Equally telling is whether customers stay.
Long-term, repeat relationships (particularly multi-decade ones in regulated sectors) are a far stronger signal than a glossy capability statement.
Look out for: a track record measured in decades, customer relationships lasting years, and longstanding approvals from recognised bodies going back further than you might expect.
Being told a company has a quality team isn’t the same as having a quality process. Ask what metrology equipment they use, whether they follow recognised frameworks like APQP, PPAP, and PFMEA, and whether inspection happens in a controlled environment.
A CMM (co-ordinate measuring machine) from a leading manufacturer, capable of inspecting to single-digit-micron tolerances, tells a very different story from a supplier relying on hand tools and goodwill.
Look out for: named equipment from recognised brands, inspection tolerances measured in microns, a temperature-controlled metrology environment, and structured frameworks rather than an informal “check it and see” plan.
A genuine plant list is harder to fake than a capability statement, and it tells you a lot. Look for the breadth of axis configurations (3-, 4-, and 5-axis), multi-spindle turning, gear cutting via power skiving or hobbing, and automation, such as pallet systems, for unmanned running.
Established global machine brands (such as DMG Mori, Okuma, Grob, etc.) are a meaningful indicator of investment compared with unbranded equipment. A narrow machine list will quietly steer every job toward what a shop already owns, whether or not it’s genuinely the best method for your component.
Look out for: a detailed, specific plant list with named machines and tooling capacity, including 5-axis mill-turn and dedicated gear manufacturing if your parts require them.
Every customer eventually has a deadline crisis. Some businesses simply say no; others say yes and quietly drop quality controls. Neither is what you want.
The best answer involves infrastructure, automated pallet systems and 24/7 lights-out running that genuinely increases throughput rather than just asking machinists to work faster.
Look out for: a structured rapid-response capability built on automation, not unofficial favours, and reassurance that urgent jobs still go through full inspection and sign-off.
A supplier who only ever quotes exactly what’s on the drawing is providing a transactional service. One who occasionally comes back with, “Have you considered this instead?” is offering something closer to a partnership.
Good value engineering input can reduce cycle times or material waste without compromising function, and it requires a supplier who understands your component well enough to offer an informed opinion.
Look out for: real examples of design input that improved manufacturability or cost, and a stated approach of collaborating with customers from the design stage rather than just executing drawings as received.
No supplier is infallible, and the ones who claim otherwise are the ones to be most cautious of.
What matters most is the process after the mistake. Is there a formal corrective action procedure, full batch traceability back through the production run, and proactive communication rather than silence?
Ask about zero-defect agreements with existing customers; these only exist where a track record has earned that level of trust.
Look out for: a clear non-conformance process, full traceability, honesty about past issues rather than denial that any occurred, and, ideally, evidence of formal zero-defect agreements already in place.
None of these questions has a single “correct” answer that fits every project. A simple bracket doesn’t need the same scrutiny as a flight-critical component.
But asking these seven questions, and listening to how confidently and specifically they’re answered, will tell you more in twenty minutes than any brochure will.
The suppliers worth working with won’t be flustered by any of these questions. They’ll have the certificates, equipment list, and examples ready because they’re proud of what sits behind the answers.
At R E Thompson, these are exactly the kinds of questions our customers have asked us over more than 78 years in precision engineering, and we’ve built our business around answering them properly.
If you’d like to put these questions to us directly, we always welcome the conversation. Get in touch with our team today.
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26 May 2026
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