CNC Machining Prices October 26, 2026: Why The Same Drawing Comes Back At $26 And $54

You sent one drawing to four shops. The quotes came back at $26, $38, $47 and $54 per piece. Nobody is padding and nobody is wrong - they priced different things. This week we are not reporting a metal index. We are opening one real part all the way down: a 6061-T6 aluminium housing, 120 × 80 × 35 mm, five-sided, two Ø8H7 bores, four M4 threads, black Type II anodize. At 10 pieces it prints $53.58 each. At 500 pieces the identical part prints $25.97 each. The difference is not margin - it is $27.61 of setup, inspection, re-fixturing and scrap allowance that stops amortising once you cross about 50 pieces. Below that line, we list the six drawing details that account for $26.92 per part - more than the entire gap between your cheapest and most expensive quote. If you change nothing else this quarter, change those six.

The reference part used throughout this article: 6061-T6 aluminium housing · envelope 120 × 80 × 35 mm · material removal 68% of blank · five-sided machining · 2 × Ø8H7 through-bores (H7 = +0.015 / 0 mm) · 4 × M4×8 threaded holes · 6 × Ø4.5 mm clearance holes · one 28 mm deep pocket · general tolerance ±0.10 mm · Type II black anodize, 8–12 µm · FAI report required on first article.

This is the single most useful number in CNC buying, and almost no shop will show it to you: the split between costs that scale with quantity and costs that do not. Material, machine time and finishing scale. Programming, fixturing, first-article inspection and lot-minimum charges do not - and on a short run those fixed lines dominate the part.

Two things in that table decide most sourcing outcomes. First, $11.18 of the $53.58 - setup, the anodize lot minimum and the FAI report - is fixed cost that simply disappears at volume. If you are running 10 pieces, you are not buying a part, you are buying a setup plus ten parts. That is why prototype pricing looks irrational and why quoting 10 pieces against an annual 800-piece programme changes the whole conversation. Second, the scrap allowance difference (8% vs 2%) is a process-maturity figure, not a material figure - it is what you pay for a shop that has not run your part before, and it is the line most likely to be quietly inflated when a drawing is vague.

Here is where a buyer has real leverage, and it is not in negotiation - it is in the drawing. These six items are the difference between a part that costs $53.58 and one that costs about $26.66 at the same quantity, with no change in function. Every one of them is a decision made before the RFQ goes out, and every one of them is invisible once the quote arrives.

Read the thin-wall line first, because it is the one that surprises people. A 1.2 mm aluminium wall is not a little harder than a 2.0 mm wall - it is a different process. Cutting forces deflect the wall, so the shop drops feed and depth of cut, adds a finish pass after stress relief, and still scraps roughly one part in seven. Going to 2.0 mm removes $6.10 per part on a 10-piece run, and on most enclosures the wall is not in the load path at all - it is there because someone dimensioned a rib and never revisited it.

The internal-radius line is the cheapest fix in engineering terms. A R0.5 corner forces a Ø1 mm end mill, and a Ø1 mm cutter removes material at roughly a fifth the rate of a Ø6 mm one while breaking far more often. Unless a mating part actually seats in that corner - and usually nothing does - writing "R2.0 max" or simply "R" on the drawing takes $3.85 off the part and makes the supplier's process dramatically more reliable.

A $26 quote against a $38 quote on the same drawing is not automatically a bargain. Here are the six places the money reappears, in the order we see them:

The price is real but the quantity is not. The quote is priced at 100 pieces while your RFQ said 20, or it carries a minimum-order charge that only appears on the invoice. Always confirm the exact quantity the unit price is built on, and ask for the MOQ in writing.

The material is substituted. "Aluminium" is not a grade. We have seen 6063 quoted against 6061-T6 and unreported secondary alloy against certified primary metal. 6061-T6 and 6063-T5 differ by roughly 90 MPa in tensile strength - about 30% - and the part will still look identical on arrival. Require the grade and temper on the certificate.

Inspection is unbundled. The part price looks sharp and then a first-article report appears at $150 to $400, or dimensional data is "available on request" at extra cost. State the inspection deliverable in the RFQ, not after the PO.

The finish is downgraded. Type II anodize at 5 µm against a specified 8–12 µm passes a visual check and fails in service - and black dye without proper sealing bleaches within months outdoors. Specify type, thickness and seal, and ask for the thickness reading on the report.

Packing is not specified, so it is not done. Carbon steel and 17-4PH parts shipped without VCI protection and desiccant arrive with surface rust after five weeks at sea. The saving is about $0.40 per part; the rework is the whole order.

There is no rework or scrap-replacement clause. If three parts out of fifty fail incoming inspection, who pays for the replacement run and the second setup? Get it in the PO. Without it, a "cheap" supplier becomes an expensive one the moment anything goes wrong.

Metal is a minority of a machined part's cost - roughly 12% on our reference part at 10 pieces - but it is the line that moves without warning. This week aluminium extended its advance: 6061-T6 plate and bar stock printed $4.85/kg, up 2.10%, the second consecutive weekly gain and the direct follow-through from the inventory draw that showed up in the national stock figures two weeks ago. Carbon steel rose harder in percentage terms, with 1018 at $1.28/kg (+2.40%) and 1045 at $1.42/kg (+2.16%), continuing the plate-side firmness.

Copper and brass went the other way. C11000 printed $16.20/kg, down 0.73%, and C36000 brass eased 0.58% to $8.60/kg - but brass carries a two-to-four-week lag against the exchange, so most of that decline has not reached a finished-part quote yet. If you machine brass or copper, the November print is where the copper move shows up, not this one. Titanium followed its own chain: Gr2 bar at $21.41/kg (+2.14%) and Gr5 at $33.83/kg (+2.73%), driven by a 4.37% move in magnesium rather than by titanium demand.

Machine-Hour Rates You Can Check A Quote Against

These are the numbers a shop multiplies by cycle time, and they are the reason a $26 quote and a $54 quote can both be honest. Ask which rate your part was priced at - it tells you more than the total does.

The practical use of that table: if a shop quotes a five-sided housing at a 3-axis rate, ask how many setups are in the cycle time. Five-axis at $78/hour beats three setups on a 3-axis at $32/hour whenever the part needs more than two repositionings - the machine rate is higher but the total is lower, and datum error drops with every setup you remove.

The step is not linear and the biggest single drop is between 10 and 50 pieces. Below 50 pieces you are paying for setup; above it you are paying for metal and machine time.

Two buying lessons come out of that curve. If your annual requirement is 400 pieces, quoting 50 at a time costs you roughly $6,600 a year against two orders of 200. And if you genuinely need five prototypes, accept that you are buying engineering time, not parts - a $447 prototype order that validates the design is cheap, and trying to negotiate it down to production pricing just means the shop drops the process work that made it worth building.

Buyers ask for "the lead time" as if it were one number. It is eight activities, and only three of them happen on a machine.

The line that costs buyers the most time is material procurement on a non-stock grade. Specifying a grade the shop has to mill-order adds three to five weeks before a single chip is cut - and in most cases a stock grade meets every requirement on the drawing. Ask "is this grade in stock?" before you ask for a faster lead time. The second avoidable delay is first-article sign-off sitting in an inbox: the clock stops at your desk, not at ours.

A shop that does not know something will assume the expensive version of it. Every gap in an RFQ becomes a risk allowance in the price, and the allowances compound.

The first line is worth restating: annual volume is the single largest unknown in a machining quote, and it is the one buyers withhold most often. A shop quoted 20 pieces prices a 20-piece job. Tell it 400 pieces across the year and the same shop prices setup amortisation, tooling and material buying completely differently - that disclosure alone is worth 25 to 35%.

Mill-direct CNC machining across milling, turning and multi-axis work, covering prototype through production volume. Every quote is issued line-by-line in USD with the machine-hour rate and quantity basis stated. Material certification per EN 10204 3.1 available on request; full FAI and Cpk data supplied with first articles.

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