Comparing CNC Quotes From China: What the Spread Means
Short answer: get three quotes for the same machined part from China and you will often see prices spread 2–3×. The spread is rarely the factory being greedy or incompetent — it is usually different assumptions hiding in each quote: tolerance class, material grade, whether finishing is included, inspection depth, and quantity breaks. A $4 part and a $12 part can be the same part quoted under different rules. Your job is to compare the assumptions before you compare the numbers.
Every week a buyer sends us a drawing and says "another factory quoted half your price." Sometimes that factory is genuinely cheaper. Often it has assumed ±0.5 mm where the drawing says ±0.05 mm, quoted domestic 6061 where the drawing says 6061-T6 with an MTR, or quietly left out the anodizing, the deburring, the inspection report, or the packaging. As a source factory in Dongguan machining parts daily, we would rather you understand the spread than chase it. This guide shows what actually varies between quotes and how to compare them fairly.
Where the Spread Comes From
A CNC quote is a bundle of decisions, and each decision moves the number. The largest levers, in rough order of impact: material grade and source, tolerance interpretation, finishing scope, quantity and batch assumptions, inspection and documentation, and freight terms. Two factories quoting the same STEP file can differ on every one of these and land 200% apart while both being "correct" on their own terms.
| Quote lever | Cheap quote assumption | Expensive quote assumption | Typical price swing |
|---|---|---|---|
| Tolerance | ±0.2–0.5 mm, no GD&T check | ±0.01–0.05 mm with full GD&T verification | +30–80% |
| Material grade | "6061" domestic, no certificate | 6061-T6 with mill certificate | +10–30% |
| Finishing | Bare machined, no deburr spec | Anodize or plating included, masked | +15–60% |
| Inspection | Visual + spot check | Full dimensional report per batch | +5–15% |
| Quantity | Volume assumptions you did not state | Exact quantity with setup amortized | Up to 2× on small batches |
The first question to ask any low quote is therefore not "why so cheap" but "what did you assume." The factory that answers with your actual tolerance, material and finish requirements is quoting the same part as you. The factory that mumbles about standard practice is quoting a different part.
Tolerance: The Most Expensive Word in the Spread
Tolerance assumptions are where low quotes are usually born. A drawing that says "general tolerance ISO 2768-mK" means ±0.1 mm for most dimensions and ±0.3 mm for machined features over 30 mm — loose enough to machine fast. A drawing with GD&T callouts, true position 0.05 and bearing bores at ±0.01 mm is a different job entirely: slower feeds, more tool passes, CMM time, more scrap. If the cheap quote ignored your callouts, it is not a comparison, it is a different product at a different price.
| Drawing reality | Fair machining tolerance | Effect on price vs loose |
|---|---|---|
| Cosmetic bracket, no mates | ±0.1 mm | Baseline |
| Holes that locate other parts | ±0.05 mm | +10–20% |
| Bearing bores, critical fits | ±0.01 mm | +25–50% |
| Ground or lapped features | ±0.002–0.005 mm | +80–200%, special process |
At BQUQ we hold ±0.005 mm on production parts where the drawing demands it, and we quote from your actual callouts. If you want to know what a factory can genuinely hold before comparing quotes, our CNC machining tolerances guide explains the classes in plain terms. The practical move: put every functional tolerance on the drawing and refuse to compare quotes that do not state the tolerance they priced.
Material Grade and Certificate Assumptions
"6061" and "6061-T6" are different line items. So are "stainless steel" (which 300-series?), "brass" (C360 or C260?), and "aluminum" with no alloy at all. Low quotes often price the cheapest stock that could charitably be called your material. Domestic Chinese 6061 vs imported billet can differ 10–20% in price and visibly in machining consistency — and it is why buyers who need traceability ask for material certificates. If your part is structural, medical, aerospace or safety-related, state the grade and ask for the MTR in the quote; see our material certificates guide for how to read one. If it is a cosmetic bracket, you may not need the certificate — but then do not pay for it either. Decide once, at quoting time, and the spread shrinks.
Finishing and Secondary Work: In or Out?
The single most common cause of "my parts arrived and the quote did not cover that" is finishing scope. Anodizing, bead blasting, plating, passivation, silk-screening, thread inserts, and even simple deburring are all sometimes included and sometimes quoted as extras. A bare-machined quote can look 20–40% cheaper than one that includes masking and black anodize — and the parts will look it. When you compare quotes, build a checklist: deburr method, surface finish spec, anodize type and color, masking requirements, marking, and packaging. If a quote is silent on finishing, assume it is excluded and ask. Our CNC finishing options guide lists what each finish actually costs and changes, so you can scope every quote identically.
Quantity, Setup and the Hidden Per-Part Math
Setup cost — programming, fixturing, first-article inspection — is a fixed fee spread across the batch. At 10 pieces it can be 50% of the quote; at 1,000 pieces it nearly vanishes. Comparing a 500-piece quote from one factory against a 100-piece quote from another is meaningless, and factories routinely quote "best quantity" assumptions when you give a range. State the exact quantity and ask what the setup fee is. Then check the drop: moving from 10 to 100 pieces should cut per-part price roughly 30–50%; from 500 to 5,000 far less, because material and cycle time now dominate. If a quote does not fall with quantity, the factory is padding setup or not planning to run your parts efficiently.
How to Compare Three Quotes Like an Engineer
Build a one-page comparison, not a gut feel. Columns: material grade + certificate, tolerance class priced, finishing included, inspection included, setup fee, per-part price at your exact quantity, tooling cost, lead time, freight terms, and payment terms. Put the same drawing, same quantity, same finish spec in front of all three. Then read the numbers: the cheapest quote that matches your spec on every row is the real cheap quote. The one that quietly fails a row is not cheaper, it is incomplete — and chasing it usually ends in rework, expedite fees, or a second supplier at the last minute. This is the same discipline described in our CNC RFQ guide and in the wider China sourcing red flags list, and it takes twenty minutes.
One more practical point: ask every factory the same three questions — what tolerance did you price, what material grade with what certificate, and what does the inspection report cover. At BQUQ those answers come back with the quotation, because we quote from your actual drawing, machine to it, and report what we measured. If a factory cannot answer the three questions, it is not quoting your part yet.
Frequently Asked Questions
Q: Why is one CNC quote from China three times another for the same part?
A: The most common reasons are different tolerance assumptions, cheaper material grades, finishing or inspection left out of the quote, and different quantity breaks. Ask each factory what tolerance, material grade and scope they priced before comparing — a quote is only comparable when every row covers the same spec.
Q: Should I always take the lowest CNC quote?
A: No. Take the lowest quote that matches your drawing's tolerance, material and finishing requirements on every line. A quote that is low because it assumed ±0.5 mm tolerances or bare aluminum will cost you rework and delays later. Compare assumptions first, then price.
Q: What should I send to get comparable quotes from Chinese CNC factories?
A: A STEP or STP file plus a PDF drawing with tolerance callouts, material grade, finish spec, exact quantity and target lead time. Missing details force factories to guess, and each factory will guess differently — which is precisely how uncomparable quotes happen.
Q: Are Chinese CNC quotes lower because quality is lower?
A: Not automatically. Lower labor cost and vertically integrated supply are honest reasons for lower prices. Protect yourself by checking the three assumptions — tolerance, material, inspection scope — and by ordering a sample batch with a dimensional report before committing to volume.
Q: How do I get a clean baseline quote from BQUQ to compare against?
A: Send the STEP file and PDF with material, quantity and finish notes to sc@bquq.com or WhatsApp +86 13713157787. You receive a quotation within 12 working hours stating the tolerance, material and inspection included, so you can compare it line by line against any other quote.
Related Resources
- CNC machining cost guide — the eight factors that set per-part price and where cost is actually made.
- CNC machining and milling services — quote-to-delivery machining at ±0.005 mm from our Dongguan factory.
- About BQUQ — an ISO9001-certified source factory running CNC, stamping, spring and heat sink lines under one roof.
- Contact us — send drawings and compare our itemized quote within 12 working hours.
Authored by the BQUQ Engineering Team. BQUQ is an ISO9001-certified source factory in Dongguan, China, running CNC machining, metal stamping, custom springs, heat sink and collet lines under one roof. Send drawings to sc@bquq.com or WhatsApp +86 13713157787 for a quote within 12 working hours. www.bquq.com
