Every machine shop has seen it: an RFQ arrives with a drawing, a quantity, and not much else. The shop guesses at the gaps, pads the quote to cover the unknowns, and the buyer ends up paying for ambiguity. A well-written RFQ does the opposite. It gives the shop everything it needs to quote tight, quote fast, and quote right the first time. Here is what to include.
What information does a machine shop need to quote your part?
At minimum, a shop needs the part drawing or model, the quantity, the material, and the delivery expectation. But the accurate quotes come from the details underneath those basics. The more the shop knows, the less it has to assume, and every assumption is either risk it prices into the quote or a surprise that shows up later as a change order.
What file format should you send?
Send a fully dimensioned drawing, preferably in PDF, alongside a 3D model in STEP or Parasolid format. The model lets the shop program and check machinability. The drawing carries the information a model cannot: tolerances, surface finishes, GD&T callouts, thread specs, and inspection requirements. If you send only a model with no drawing, the shop has no controlling document to inspect against, and quality work becomes impossible to guarantee. If you send only a PDF with no model, programming takes longer and costs more.
How should you specify material?
Name the material and the specification, not just the family. “Aluminum” is not enough. “6061-T6 per AMS 4027″ tells the shop exactly what to buy, what it costs, and how it machines. For regulated work, specify whether you require domestic material, mill certifications, or a particular heat treat condition. Material callouts drive a large share of the part cost, so vague material specs produce vague quotes.
How tight should your tolerances be?
Specify only the tolerances the part function requires. Blanket tight tolerances across every dimension can multiply cost without adding value, because each tight feature adds setups, inspection time, and scrap risk. Call out the critical dimensions clearly and let the general tolerance block cover the rest. If a shop like MTI can see which features are critical and which are not, we can machine efficiently where we can and hold precision where it matters.
What quality deliverables should you specify up front?
If you need a first article inspection report to AS9102, a certificate of conformance, material certifications, or specific inspection data, put it in the RFQ. These deliverables take real time and belong in the quote from the start. Requesting them after the fact leads to delays and repricing. For aerospace, defense, and medical parts, spell out the quality requirements exactly the way your program demands them.
How does quantity affect your quote?
Tell the shop whether this is a one-off prototype, a production run, or a blanket order with releases over time. The quantity changes the entire approach: setup cost gets amortized differently, material gets bought differently, and fixturing decisions change. A shop can often lower your per-part price significantly at higher volumes, but only if it knows the volume when it quotes.
What about lead time?
State your required delivery date and flag whether it is firm. If the timeline is tight, say so up front so the shop can quote against real capacity rather than assuming a standard lead time. If the date is flexible, that flexibility can sometimes lower your price. Either way, an honest timeline produces an honest quote.
A simple RFQ checklist
Before you send your next machining RFQ, confirm it includes the dimensioned drawing and 3D model, the material and specification, the critical tolerances, the quantity or release schedule, the required quality deliverables, and the delivery date. Those six items turn a guessing game into a firm number.
MTI is an AS9100D and ISO 9001:2015 certified precision machining and fabrication shop serving the aerospace, defense, and medical industries. Send us a complete RFQ and we will quote it accurately, machine it to spec, and document it to your requirements.