CNC Quote: 7 Steps to an Accurate Price
A CNC quote is only as good as the information behind it. This guide is for design engineers and buyers who send RFQs and want a number they can actually commit to. Read it once and you will know exactly what to attach, what to flag, and what to leave out.
In this article
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What actually moves a CNC quote
What a CNC quote needs from your files
The fastest way to slow down a CNC quote is to send a screenshot. A STEP file gives us the geometry. A 2D PDF gives us the intent. Send both and the estimator does not have to guess which face is the datum. If you only have a 2D drawing, send it as a vector PDF, not a scan, because we need to read dimensions and not squint at pixels.
Mark the critical dimensions. If a bore is ±0.02 mm and a mounting hole is ±0.2 mm, say so on the drawing. When every dimension carries the same tight tolerance, the estimator has to quote the whole part to the tightest callout. That is the single most common reason a quote comes back higher than expected.
Tell us the function in one line. A bracket that holds a cover and a bracket that sees 8 kN of vibration look similar on paper but get different process plans. We do not need a full report in the first email. One sentence about load, temperature, or mating parts is often enough to pick the right stock and cut sequence.
Include the revision letter and a date on the file name. We have quoted rev C while the customer was working in rev E, and nobody noticed until the first article. A file named 4021-bracket-revE-2026-02-14.step takes two seconds to check.
- 1SendSTEP or X_T solid, 2D PDF with GD&T, material grade, quantity, finish.
- 2SkipRendered images, hand sketches, and assemblies with 40 parts unless they are all in scope.
- 3FlagThin walls under 0.8 mm, deep pockets over 4× diameter, and any feature needing a 5-axis setup.
Tolerance, material, and finish: where the money goes
Tolerance is the biggest lever. At ±0.05 mm, a 3-axis mill with standard workholding handles most aluminum and steel parts. At ±0.005 mm, we are measuring with a CMM, controlling temperature, and often leaving stock for a finish pass. Both are doable. They are not the same price.
Surface finish follows the same logic. Ra 3.2 μm comes off the tool. Ra 0.8–1.6 μm needs a lighter stepover and a sharper insert, so cycle time climbs. Below Ra 0.8 μm you are usually talking about polishing or a specialty process, and that is a separate operation with its own handling risk.
Material grade and temper matter more than most buyers expect. 6061-T6 chips cleanly and holds tight tolerances. 304 stainless work-hardens, so we slow the feed and accept more tool wear. Titanium Ti-6Al-4V needs lower cutting speeds and more coolant. Inconel is slower again. If you can use 6061 instead of 304, say so and ask for both numbers.
Anodizing, plating, and powder coating are quoted as operations, not as a line item on the drawing. Hardcoat anodizing adds thickness that changes a press fit. Electroless nickel can build 0.025 mm per side. Tell us which dimensions must survive the coating, and we will mask or compensate.
- 1Price break point±0.05 mm and Ra 1.6–3.2 μm is the standard band for 3-axis work.
- 2Cost step up±0.005 mm, Ra 0.2–0.8 μm, or a 5-axis setup adds time and inspection.
- 3Free substitutionChanging 304 to 6061 or 316L to 303 can cut cycle time without changing function.
How quantity and lead time change the CNC quote
At one piece, the part is machined from billet with soft jaws or a vise, and programming is spread across a single unit. At 100 pieces, we might make a fixture. At 10,000 pieces, a dedicated fixture and a bar feeder start to pay for themselves. That is why the unit price curve is steep at first and flattens later.
Ask for three quantities. A quote at 1, 50, and 500 pieces shows you where the setup cost amortizes. Sometimes the 500-piece price is close to the 50-piece price because the setup is already absorbed. Sometimes it is not, because the part needs a second operation that only makes sense at volume.
Lead time is not a single number either. We can return a quotation and free DFM analysis within 12 hours, and production can start within 24 hours after you approve. Standard parts ship in 3–5 days. If the part needs hardcoat anodizing or a CMM report, add time for that operation rather than assuming it is included.
The historical late-delivery probability on our side is below 2%. That number comes from planning, not from rushing. If a finish vendor is the bottleneck, we will tell you at quote time instead of at ship time.
- 1Prototype quantity1 to 10 pieces, no minimum order quantity, quickest route to a fit check.
- 2Bridge quantity50 to 500 pieces, usually where a fixture and a second setup get justified.
- 3Production quantity1,000 to 10,000+ pieces, where cycle time and material yield dominate the price.
What makes a CNC quote come back wrong
The most common problem is a missing callout. If a hole pattern has no tolerance, the estimator assumes a general tolerance, which is often ±0.1 mm or looser. If your assembly needs ±0.02 mm, the quote is technically correct for the drawing you sent and wrong for the part you need.
The second problem is an unstated finish. A part quoted as machined aluminum and then anodized black is a different scope. The anodizer needs racking points, the threads need masking, and the color match has a batch tolerance. All of that should be in the first RFQ.
The third problem is a geometry that cannot be held. A 0.5 mm wide slot that is 20 mm deep is a broken end mill waiting to happen. A wall 0.4 mm thick on a 100 mm long steel part will move during machining. We will flag these in the DFM analysis, but flagging them after the quote costs everyone a day.
The fourth problem is a silent revision. If you change a dimension after quoting but before the PO, send the new file. We re-quote for free. Machining to a stale model is expensive for both sides.
- 1Missing toleranceUnmarked dimensions fall back to general tolerance, which may not fit your assembly.
- 2Unstated finishAnodize, plating, and masking must be in the RFQ, not added at PO stage.
- 3Unmachinable featureDeep narrow slots, thin walls, and sharp internal corners need a design change.
- 4Stale revisionAlways re-send the current file so the quote matches the model.
How to prepare and send a CNC quote request
Follow these in order. Each step takes minutes and removes one round of email.
- 11. Export a STEP or X_T solidUse AP214 or AP242. Check the file opens without missing faces. Name it with the part number and revision, for example 4021-bracket-revE.step.
- 22. Attach a 2D PDF with GD&TShow datum features, critical dimensions, and thread callouts. Use vector PDF. Mark tight tolerances such as ±0.005 mm and leave non-critical dims to the general tolerance block.
- 33. State material grade and temperWrite 6061-T6, 304, 17-4PH (SUS630), TC4 (Ti-6Al-4V), or POM. If the grade is flexible, list a first and second choice and ask for both prices.
- 44. Declare finish and maskingSpecify anodizing type and color, plating, powder coat, or as-machined. Note any dimension that must survive coating, since hardcoat can build 0.025 mm per side.
- 55. Give three quantitiesAsk for 1, 50, and 500 pieces, or whatever range fits your program. This shows where setup cost amortizes and whether a fixture is worth building.
- 66. Note inspection and documentationSay whether you need a first article report, a CMM report, material certs, or full traceability. We inspect 100% before shipment and reports are available on request.
- 77. Mention the deadline and NDAGive the date you need parts, not the date you want a quote. If confidentiality matters, request an NDA before sending files and we will sign it.
- 88. Review the DFM notes before you approveRead the flagged features. If we suggest a 0.2 mm corner radius instead of a sharp internal corner, that is a tooling reality, not a preference.
What raises a CNC quote and what keeps it low
Same part, different specifications. Use this to decide which requirements are worth paying for.
| Specification | Lower-cost choice | Higher-cost choice | When the higher cost is justified |
|---|---|---|---|
| Tolerance | ±0.05 mm general | ±0.005 mm critical features only | Mating bores, bearing seats, press fits |
| Surface finish | Ra 1.6–3.2 μm as machined | Ra 0.8–1.6 μm or polished | Sealing faces, sliding contact, optics |
| Material | 6061-T6 aluminum | 304, 17-4PH, Ti-6Al-4V, Inconel | Corrosion, strength, temperature, weight |
| Geometry | 3-axis, open pockets, through holes | 5-axis, undercuts, deep cavities | One-setup accuracy on complex parts |
| Finish | As machined or bead blast | Hardcoat anodize, electroless nickel | Wear resistance, conductivity, appearance |
| Quantity | 1 to 10 pieces, soft jaws | 1,000+ pieces with dedicated fixture | Unit price matters more than setup |
| Inspection | Dimensional check, 100% visual | CMM report, first article, certs | Regulated industries and audits |
The short version
A good CNC quote is a data problem, not a price problem. Send a solid, a marked-up drawing, the material grade, the finish, and three quantities. Everything else is a follow-up email you did not need to write.
CNC quote questions engineers ask
What files do you need for a CNC quote?
A STEP or X_T solid plus a 2D PDF with the critical dimensions and GD&T. If you have a native SolidWorks, NX, or Inventor file, send it. We can also quote from a 2D PDF alone if the part is simple and fully dimensioned.
Include the material grade, quantity, finish, and any inspection requirement in the same email. That keeps the first reply useful instead of a list of questions.
How fast can I get a CNC quote?
We return a quotation and a free DFM analysis within 12 hours. Production can start within 24 hours after you approve the quote and the files are released.
If your part needs a specialty finish or a CMM report and you have a hard deadline, say so in the RFQ. We will confirm the schedule before you commit.
Is there a minimum order quantity?
No minimum order quantity. We run from one prototype to 10,000+ part runs on the same process. The unit price changes with quantity because setup and fixturing are amortized differently.
For one-off parts we machine from billet with soft jaws. For repeat runs we may build a fixture, which lowers the per-part cycle time.
Can you sign an NDA before I send files?
Yes. Uploads are secure and confidential, and we can sign an NDA on request before you share drawings. Send the request through the contact page and we will return a signed copy.
If your program has export-control or ITAR-like requirements, tell us at the start so we can confirm scope before quoting.
Should I ask for multiple quantities in one RFQ?
Yes. Ask for at least three quantities, such as 1, 50, and 500 pieces. It shows where the setup cost stops dominating the unit price.
If the 500-piece price is much lower, you can plan a bridge order. If it is flat, your part is dominated by material or cycle time, and the quantity break will not help much.
Why did my CNC quote change after the first email?
Usually a drawing revision, a new finish, or a tolerance that was not on the original file. When scope changes, the quote changes with it.
We re-quote for free when you send an updated model. Machining to a stale revision is the expensive outcome, not the re-quote.
Send your files and get a number you can use
Quotation and free DFM analysis within 12 hours. No minimum order quantity, 100% inspection before shipment, and an NDA if you need one.
12-hour quoteNo MOQ100% inspectionNDA available
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