Key Takeaways
- Certifications are the first filter, not the last word. AS9100 and ISO 9001 registration tell you a supplier has a documented quality system. They do not tell you whether that supplier can hold your tolerance on your material.
- Traceability protects you during audits. Every lot should trace back to a mill certification you can produce on request. Suppliers who cannot document material origin create risk that lands on your desk, not theirs.
- Tooling charges hide the real cost. A low piece price paired with a tooling fee often costs more than a slightly higher price with no tooling charge. Compare total program cost across the expected life of the part.
- Quote speed predicts production behavior. A supplier who takes two weeks to return a quote will not suddenly become responsive once your order is on the floor. Treat responsiveness during quoting as a preview.
- A trial order tells you more than a capability sheet. Order a small run against a real print and inspect it yourself. What comes back, and how it is documented, settles most questions.
Why Supplier Selection Carries More Risk Than Price
An aircraft washer or shim is one of the least expensive items on an aerospace bill of materials, and one of the most capable of stopping a build. When a lot arrives out of tolerance, the cost is not the part. It is the line that stops, the inspection hours spent proving what went wrong, and the schedule that slips behind it.
Procurement teams under pressure to reduce spend often evaluate suppliers on unit price and lead time alone. Those two numbers say very little about whether a supplier can repeat a result across twelve deliveries over three years.
We have manufactured precision components since 1919, and the questions below are the ones we would want a buyer to ask us. They are ordered roughly the way a qualification process should run.
Start With Certifications and Registrations
Certification is where any aerospace evaluation begins, because most primes will not accept a part from an unregistered source. AS9100 is the aerospace quality management standard built on ISO 9001, adding requirements for configuration management, risk, and counterfeit-part prevention. Ask for the current certificate, check the expiration date, and confirm the scope covers the process you are buying, which, for stamped and formed parts, should name precision metal stamping rather than assembly or distribution alone.
Registration status matters as much as certification for defense-adjacent work. A supplier handling controlled technical data needs the appropriate registrations in place before you send a print, not after.
Ask when the last surveillance audit took place and whether any findings were issued. A supplier with a clean record will answer without hesitation, and one working through corrective actions will usually tell you what changed as a result. Neither answer is disqualifying on its own; evasion is.
What Each Credential Actually Tells You
Credentials are often listed together as though they carry equal weight. They don’t, and knowing what each covers keeps you from over-reading a certificate.
- AS9100: A documented aerospace quality system with defect prevention, traceability, and configuration control built in.
- ISO 9001: A general quality management baseline. Necessary, but not sufficient on its own for flight hardware.
- ITAR and DDTC registration: Confirms the supplier may lawfully receive and handle controlled technical data.
- DFARS-compliant materials: Specialty metals sourced from qualifying countries, which is required on many defense contracts.
- CAGE code: Identifies the supplier as a recognized entity in government supply chains and simplifies contract paperwork.
Verify Material Traceability and Compliance
Ask how a finished part traces back to raw stock. A capable supplier keeps mill certifications on file and can pull the record for a specific lot years after shipment. If the answer involves searching through email or calling a distributor, the traceability chain is weaker than it needs to be for aerospace and defense applications.
Material substitution is the related risk. A supplier who quietly swaps 302 stainless for 304 because it was on the shelf may deliver a part that measures correctly and behaves differently in service. Your purchase order should state that substitutions require written approval, and your supplier should treat that as normal, not restrictive.
Confirm the material range as well. We stock and process both common and semi-exotic alloys, including stainless in a variety of grades, phosphor bronze, beryllium copper, Inconel, and Monel, alongside a full list of plastics and films for non-metallic requirements.
The Procurement Checklist
Work through the following sequence in order. Each step is cheap compared to the cost of discovering a problem after the first production release.
- Confirm certification scope: Current AS9100 and ISO 9001 certificates that name the processes you are buying.
- Request a sample traceability package: Ask for a redacted certificate of conformance and mill certification from a past job.
- Test the tolerance claim: Send your tightest realistic print and ask what they would hold, not what they can hold in theory.
- Clarify tooling terms: Ask whether tooling is charged, who owns it, and whether they store it for repeat orders.
- Establish inspection expectations: Agree on sampling plans, documentation, and what accompanies each shipment.
- Review capacity and single points of failure: Ask what happens to your delivery if one machine or one operator is unavailable.
- Place a trial order: Buy a small quantity against a real requirement and inspect it against the print yourself.
Questions Worth Asking Before a First Order
The answers matter less than the specificity behind them. A supplier who has genuinely thought about your part will give you numbers and conditions, not assurances.
- “What is your realistic tolerance on this material at this thickness?” Specific answers signal experience; broad reassurance does not.
- “Do you charge for tooling, and do you keep it?” Stored tooling lowers cost and shortens lead time on every reorder.
- “How fast do you return a quote?” Quoting speed is the clearest early indicator of how a supplier is staffed.
- “What happens when a lot fails inspection?” Ask about containment, root cause, and who pays for the replacement.
- “Who actually makes the part?” Confirm whether work stays in-house or moves to a subcontractor you have not evaluated.
Capacity questions deserve the same directness. Ask how many presses could run your job, what the backlog looks like, and whether a rush order would displace your delivery or someone else’s. A supplier who has thought about capacity will answer in specifics.
Warning Signs in Quoting and Lead Times
Quotes that arrive without questions are worth a second look. A supplier reviewing a demanding print should ask about burr direction, flatness, edge condition, or how the part is used, because those details change how it is made. Silence usually means the print was priced, not read.
Be equally cautious about lead times that seem unusually short for a custom part. Aggressive promises made during the sales conversation tend to become revised dates once the job reaches the floor. We would rather commit to a date we will hit than win an order with a number we cannot support, which is why we publish our quoting turnaround and process openly on our custom precision parts page.
How to Run a Meaningful Trial Order
A trial order is the only step in this process that produces physical evidence. Structure it so the result actually tells you something.
- Use a real print, not a test coupon: Trial parts should reflect the tolerances and material you will actually buy.
- Inspect independently: Measure the parts yourself or through your own lab rather than relying only on supplied data.
- Evaluate the paperwork: Documentation quality on a small order predicts documentation quality on a large one.
- Reorder before you commit: Consistency between the first and second lot matters more than either lot alone.
If you want to review the standard itself, SAE publishes AS9100D with the full requirements for aviation, space, and defense organizations. Our company background outlines how we manage material, tooling, stamping, and inspection under one roof in Fairfield, New Jersey.
Keep the trial paperwork on file as your baseline. If quality drifts two years later, the original documentation package is what lets you show exactly what changed rather than arguing from memory.
Put Brewster Washers on Your Approved Supplier List
The suppliers worth keeping are the ones who answer specific questions with specific numbers and hold the same standard on the tenth order as the first. We have built our reputation on parts that go into flight and defense hardware, where a rejected lot is never just a rejected lot.
Send us your print, and we will return a quote within 24 to 48 hours, with no tooling charge. Request a quote from Brewster Washers to get started.