Guides / Choosing a Supplier

How to Qualify a Machine Shop for Inconel Work

September 18, 2026

A shop that says yes to any material over the phone is not proof of anything. Inconel separates real experience from willingness to try fast, and the questions below are the ones that do it before a drawing or a purchase order changes hands.

Ask what alloy and grade they run most

Skip “can you machine Inconel” and ask “which grades do you run most.” A shop that answers with a specific grade, usually 718 or 625, and can describe what it is used for (aerospace fasteners, downhole tools, exhaust components) has real production history with the alloy. A shop that answers “yes we can do Inconel” without naming a grade is often extrapolating from stainless or titanium experience, which does not transfer as cleanly as it sounds.

Ask a follow-up: how many Inconel jobs has the shop run in the last year, and in what quantity range. A shop running single prototype pieces occasionally has a different risk profile than one running repeat batches of 50 to 500 pieces.

Tooling and speeds: what a real answer sounds like

Ask what tooling and cutting speeds the shop uses on Inconel compared with steel or stainless. A shop with real time on the alloy will talk about ceramic or coated carbide inserts chosen for nickel alloys, lower cutting speeds than steel and rigid setups that keep the part from deflecting under load. It should also mention tool life as a known, budgeted cost, not a surprise.

A vague answer like “we just slow the machine down” without naming a tooling choice is a sign the shop has not run enough Inconel to have a settled process. Work hardening punishes an unsettled process quickly, showing up as chatter, dimensional drift or burned tooling partway through a run.

Mill cert verification and PMI testing

Ask how the shop verifies incoming Inconel stock. A mill certificate documents chemistry and heat number traceability back to the melt, and a shop that treats this as routine paperwork, not an afterthought, is used to buyers who care about it. Ask specifically whether positive material identification (PMI) testing is done in-house or outsourced, and whether it runs on every order or only when asked.

Neither answer is automatically wrong. A shop that outsources PMI to a local lab can still be a good fit if it does so consistently and can turn results around inside your timeline. The red flag is a shop that has never been asked the question and has no process ready to answer it.

FAI and the first production run

Ask what a first article inspection looks like at this shop and how long it typically adds to a first order. A real answer covers dimensional results tied to every drawing callout, the material certificate and a record of the process used, not just a part shipped with a checkmark. On Inconel specifically, ask whether the shop expects the first piece off a new setup to differ from the tenth, since work hardening and tool wear both shift through a run. A shop that has thought about this will build its FAI cadence around it instead of pulling one part at random.

Repeat orders, second-source risk and quotes that move too fast

Ask what happens on a repeat order six months later: does the shop keep the program, fixture and tooling notes on file, or start over. Ask whether it has ever needed a second source mid-order and how that went. These questions tell you whether the relationship holds up past the first delivery.

Watch for the opposite problem too. A shop that returns a quote in minutes on a complex Inconel part, with no questions about mill cert, PMI, FAI or spec standard, has usually not read the drawing closely enough to price it correctly. The shops worth working with ask questions before they quote, not after the part comes back out of tolerance.

If you have a drawing ready, we can match it with shops that already answer these questions the way you want to hear them answered.

Frequently asked questions

Keep reading

• Writing an RFQ for Inconel Parts That Gets a Fast, Accurate Quote
• Mill Certs and PMI Testing: Catching a Substitute Alloy Before It Ships