Aluminum sensor bracket
Aluminum 6061-T6 · 50 × 40 × 10 mm · 3-axis milled · 6 holes, 1 pocket · as-machined · ±0.1 mm general
Order total: baseline
Order total: 2.1× one part
Order total: 8.3× one part
Order total: 36× one part
CNC machining cost guide
Most cost guides say “it depends.” This one shows how much — what quantity, material, tolerances and finish do to the price of real reference parts, and how to design the cost out before you upload.
What quantity does to the price: three parts
Three reference parts, priced through the same engine that quotes every FabDigit order. Unit price is indexed to one piece (= 100) — the same curve repeats on almost every machined part.
Electronics enclosure body
Aluminum 6061-T6 · 120 × 80 × 40 mm · deep pocketing, M3 tapped holes · bead blast · ±0.05 mm on bores
One piece costs about 2.7× one bracket
Order total: baseline
Order total: 2.3× one part
Order total: 9.7× one part
Titanium manifold fitting
Titanium Ti-6Al-4V (Gr 5) · 60 × 60 × 35 mm · 5-axis · sealing faces at ±0.025 mm · as-machined
One piece costs about 5.9× one bracket
Order total: baseline
Order total: 3.3× one part
Order total: 17× one part
Indexes come from the FabDigit quote engine (September 2026) for the exact reference geometries described, rounded. They show how the price moves, not what your part costs — your part is priced on its own geometry and confirmed by engineering review before production.
Where the money goes
Four line items explain nearly every CNC price — but their shares shift dramatically with quantity. At one part, setup and programming is most of what you pay; by a hundred parts it fades to single digits and machine time plus material take over. The bars below show the mix for the aluminum sensor bracket priced above.
Qty 1index 100
Qty 10index 21
Qty 100index 8
Setup & programmingMachine timeMaterialFinishing & inspection
Card figures show each driver’s share of the unit price moving from quantity 1 to quantity 100:
58% → 7%
Setup & programming
CAM programming, fixturing, and first-piece inspection cost the same whether you order 1 part or 100. At one part it IS most of the price; at a hundred it nearly disappears.
30% → 57%
Machine time
Spindle minutes are the biggest slice once setup amortizes. Deep pockets, small internal corners, and 5-axis setups all buy more minutes.
7% → 26%
Material
You pay for the stock block your part is cut from, not the part volume. Exotic alloys flip this: titanium or PEEK stock can dominate the price.
0–100%+ adder
Tolerances & finishes
Every callout tighter than ±0.05 mm adds slower passes and more inspection. Anodize, powder coat, and plating add lot charges.
Material choice: the cost multiplier you pick first
Relative machined-part cost with aluminum 6061-T6 as the baseline. Note that the multiplier is rarely just the stock price — hard and gummy alloys also machine slower.
| Material | Typical cost vs 6061 | Why |
|---|---|---|
| Delrin (POM) | 0.8–0.9× | Cheap stock, machines fast, no work-hardening. The budget pick for jigs and non-structural parts. |
| Aluminum 6061-T6 | 1.0× (baseline) | The default CNC material: cheap stock, excellent machinability, anodizes well. |
| Aluminum 7075-T6 | 1.1–1.2× | Aerospace-grade strength; stock costs more than 6061, cuts nearly as fast. |
| Brass C360 | 1.1–1.3× | Expensive stock but the fastest-machining metal on the list — the two mostly cancel out. |
| Steel 4140 | 1.3–1.5× | Tougher on tooling, slower feeds; often needs post-machining heat treatment. |
| Stainless 304 | 1.4–1.6× | Work-hardens as you cut it — slower speeds and more tool wear than mild steel. |
| Stainless 316L | 1.5–1.8× | Gummier than 304; the marine/medical corrosion premium is machine time, not just stock. |
| PEEK | 2–3× | The stock itself is the cost: engineering-plastic billet priced like a specialty alloy. |
| Titanium Ti-6Al-4V | 2.5–4× | Expensive stock AND slow machining (low thermal conductivity limits cutting speed). |
Tolerances: priced per feature, not per part
Tightening one bore does not reprice the whole part — but a blanket title-block tolerance does. Typical impact on the affected features:
| Tolerance band | Typical price impact | What changes in the shop |
|---|---|---|
| ±0.1 mm and up (general) | Baseline | Standard milling and turning operations, standard inspection. |
| ±0.05 mm | +5–15% | Slower finishing passes, tighter tool-wear management. |
| ±0.025 mm (precision) | +15–30% | In-process metrology, temperature-stable machining windows. |
| ±0.01 mm and tighter (critical) | +40–100%+ | Grinding, EDM, or lapping as secondary operations; CMM verification on the feature. |
Surface finishes: mostly lot charges
Finishing is usually billed per lot, not per part — which makes it nearly free at quantity 100 and noticeable at quantity 1.
| Finish | Lot charge vs anodize II | Notes |
|---|---|---|
| As-machined | Included | Sharp edges broken, visible tool marks. Ra 1.6–3.2 µm typical. |
| Bead blast | ≈ 0.3× anodize II | Uniform matte texture; hides tool marks before anodizing. |
| Anodize Type II (clear or color) | 1× (reference) | Corrosion + cosmetic layer for aluminum; lot charge dominates at low quantity. |
| Anodize Type III hardcoat | ≈ 2× anodize II | Wear-resistant 25–50 µm layer; masking for tight-tolerance bores adds cost. |
| Powder coat | ≈ 1.5× anodize II | Thick cosmetic/protective layer; check tolerance stack on mating faces. |
| Laser marking (part IDs, logos, data matrix) | Free at FabDigit | Included at no extra cost on eligible parts. |
Quantity: the cheapest optimization you control
Look back at the sensor bracket: unit-price index 100 for one piece, 8 at a hundred — a 92% lower unit price for the same geometry, and a hundred parts cost only about 8× one. Nothing about the part changed; the fixed setup cost (CAM programming, fixturing, first-piece inspection) simply spread across more parts. Most of that collapse happens early: the jump from 1 to 10 pieces routinely cuts unit price by 70–80%, while 10 to 100 adds another 50–60%.
Aluminum sensor bracket — unit price by quantity
Order total: baseline
Order total: 2.1× one part
Order total: 8.3× one part
Order total: 36× one part
Practical rule: if you need 8 parts, price 10. If a revision is likely, prototype at 1–3 first — the setup you “waste” on a scrapped revision is far cheaper than 100 obsolete parts.
Eight ways to pay less for the same function
Straight from the DFM checks our engineers run on every quote. Each one is a design decision, not a negotiation.
- Tolerance only what matters. Call out ±0.025 mm on the two bores that need it, leave the rest at ±0.1 mm. Blanket title-block tolerances are the single most common overpayment.
- Avoid deep, narrow pockets. Depth beyond ~4× tool diameter forces long, fragile tools and slow stepping. Split the part or open the pocket if you can.
- Radius your internal corners. Internal corner radius ≥ ⅓ of pocket depth lets a bigger tool do the work. Sharp internal corners need EDM — a different price class.
- Use standard drill sizes. A Ø6.00 mm hole is one drill cycle; Ø6.05 mm is a drill plus a boring pass. Same for thread sizes — M3/M4/M5 beat oddballs.
- Keep walls above 0.8 mm. Thin walls chatter, which means slower feeds and scrapped parts priced into the quote.
- Design for one setup. Features reachable from one direction machine in one clamping. Every extra setup adds fixturing and re-indication cost.
- Match stock sizes. A 51 mm-tall part cut from 55 mm plate wastes a machining pass and a stock premium a 50 mm design avoids.
- Order at quantity breaks. Setup amortizes fast: if you need 8, quote 10. The 10-piece unit price is often low enough that two spares are free.
CNC machining cost — FAQ
How much does CNC machining cost?
It depends on geometry, material, tolerances, finish and above all quantity. For a small aluminum 6061 bracket run through the FabDigit quote engine, the unit price at 10 pieces is 79% lower than at one piece and at 100 pieces 92% lower — ten parts cost about 2.1× one part in total. Machine time, setup amortization, material, and tolerances are the four drivers; upload CAD for the price of your part.
Why is one prototype so expensive compared to the per-part price at 100?
CAM programming, fixturing, and first-piece inspection cost roughly the same for 1 part as for 100. At quantity 1 that fixed setup cost IS most of the price; at 100 it spreads to pennies per part. That is why unit price typically falls 75–90% between quantity 1 and quantity 100.
What is the cheapest material for CNC machining?
Aluminum 6061-T6 is the cost baseline for metals — cheap stock and excellent machinability. Delrin (POM) machines even cheaper for non-structural plastic parts. Stainless steels run roughly 1.4–1.8× the price of 6061, and titanium 2.5–4×.
How much do tight tolerances add to the price?
Moving from a general ±0.1 mm tolerance to ±0.05 mm typically adds 5–15% on the affected features. ±0.025 mm adds 15–30% with in-process metrology, and ±0.01 mm or tighter can add 40–100% or more because it usually requires grinding or EDM plus CMM verification. Tolerances are priced per feature — only the callouts you tighten cost extra.
How do I get an exact price for my part?
Upload your CAD file to FabDigit for an instant quote — the same pricing engine behind the figures in this guide reads your geometry, material, tolerance callouts, and quantity, and returns a price in minutes. Every order is then confirmed by an engineering review before production.
Why does this guide show indexes instead of dollar prices?
A dollar figure is only true for one geometry, material, quantity and finish. What carries over to your part is how the price moves, so the examples index the unit price to one piece (= 100) and give materials, tolerances and finishes as multipliers. Your part is priced on its own geometry, and engineering review confirms every order before production.
Choosing a supplier as well as a price? The online CNC machining services comparison puts FabDigit, Xometry, Protolabs, Fictiv and others on the same verified columns — lead time, minimum order, tolerance, certifications.
Your part has its own number.
Upload a CAD file and the same engine behind this guide prices your geometry in minutes — with an engineering review before anything hits the floor.