Why 40 CNC Parts Cost More Per Piece Than 4,000
A customer asked us to quote 40 simple aluminium parts. The honest unit price was uncomfortable — so we didn't send one. We sent the cost breakdown instead. This is what small-batch machining actually costs, and how to read a low-volume quote.
The Quote Nobody Enjoys Sending
A while back a customer came to us with 40 aluminium parts. Simple parts — nothing exotic, a mix of milling and turning operations, tolerances that any competent shop would call routine.
We ran the numbers and the unit price came out high. Not "we're busy so here's a padded number" high — genuinely, structurally high, for a reason that has nothing to do with the part and everything to do with the quantity.
Sending that number on its own would have been a bad idea. The customer would have seen a price several times what they'd expect to pay per piece at production volume, concluded we were taking advantage, and gone shopping. That's what happens to most small-batch quotes, and it's a shame, because the number is usually fair.
So we didn't send a unit price. We sent the arithmetic.
Where the Money Actually Goes
Here's the part that isn't obvious until you've run a shop: most of what you pay for in a small batch doesn't scale with quantity.
Programming the job in CAM takes the same hours whether you cut 10 parts or 10,000. Designing and building the workholding takes the same time. Proving out the first part — running it, measuring it, adjusting offsets until it's right — takes the same time. Then material: at 40 pieces you buy from a local stockist at retail-ish rates, not from the mill in coil quantities.
None of those costs care how many parts you order. Which means the fewer parts you order, the more each one has to carry.
| Cost element | Scales with quantity? | What it means at 40 pcs |
|---|---|---|
| CAM programming | No — fixed | Same hours whether 1 or 1,000 |
| Workholding / setup | No — fixed | Fixture or vice setup is identical |
| First-piece prove-out | No — fixed | Run, measure, adjust offsets — once |
| Tooling | Partly | Tool wear scales, but setup does not |
| Material | Yes | Higher per kg at small quantities |
| Machine time | Yes | Cycle time per part, with no volume to optimise against |
| Inspection & packing | Partly | Report setup fixed, per-part checks scale |
At 4,000 pieces those fixed hours get divided 4,000 ways and effectively vanish. At 40 pieces they get divided 40 ways and dominate. Same part, same machine, same machinist — completely different unit cost. That's the whole story.
What We Sent Instead
Rather than a single price per piece, we laid out what the job actually consumed:
- One machine, occupied for the job
- One senior machinist, on it from programming through to finished parts
- One full working day, start to finish
- Plus the overhead that comes with running a shop at all
That's it. No padding, no mystery margin, no "small order surcharge." Just: here is the machine, here is the person, here is the day, here is what that costs. The customer is then in a position to judge whether it's fair, instead of having to guess.
This is not a clever sales technique — it's just the honest shape of the work. A job that occupies a machine and a skilled machinist for a day costs what a machine and a machinist cost for a day. Whether you make 40 parts in that day or 400 is a question of cycle time, not of principle.
What happened next
The customer approved it and paid the same day. We programmed, machined, inspected and handed the parts to DHL the same day the payment cleared.
Worth being clear about why: it wasn't that the price was low. It was that the price made sense. Nobody likes paying more per piece than they expected — but people accept it readily once they can see it isn't arbitrary. Once the number is explainable, the conversation moves from "why so expensive" to "when can you start."
How to Read a Small-Batch Quote
If you're buying 10–100 machined parts, these four questions will tell you more than comparing raw numbers between suppliers.
1. Ask for setup cost separated from unit price
Any shop that knows its own numbers can split them. Once you see the split, the unit price stops looking arbitrary — and you can see exactly what the second batch would cost, minus the setup you've already paid for.
2. Ask whether a design change would cut the setup
Often it's one feature driving the cost: a deep pocket that forces a long thin tool and slow feeds, an internal sharp corner that needs a tiny cutter, a tolerance on a face that does nothing. Ask. A good shop will point at it.
3. Ask for two quantities side by side
Get a quote at 40 and at 200. The jump is usually far smaller than people expect, because the fixed cost is already absorbed. This is the single most useful piece of information in a small-batch quote, and almost nobody asks for it.
4. Check whether the tolerances are all actually needed
If every dimension is called out at ±0.01mm, the shop has to assume they all matter — and machine accordingly. Tolerate the fit, not the part, and the quote usually drops. We wrote up what each process can realistically hold if you want the numbers.
When We Tell People Not to Order Yet
This costs us short-term revenue and we do it anyway, because the alternative is a customer who feels burned.
- The design isn't frozen. If you're still moving holes around, wait. Every revision after setup means paying for setup twice. Pay once, on the final geometry.
- You'll need 500 next quarter. If that's likely, order a slightly larger first batch or at least get both quotes now. Two separate 40-piece setups cost far more than one 80-piece setup.
- The part is simple enough for a different process. Sometimes the honest answer is that extrusion plus a couple of drilled holes beats machining the whole thing from solid. We'll say so.
- You're comparing against a mass-production price. If your internal benchmark came from a 10,000-piece run, no supplier will match it at 40. That's arithmetic, not pricing policy.
None of this is anti-sales. A customer who understands why a small batch costs what it costs comes back for the production order. A customer who feels overcharged on the prototype doesn't.
Small-Batch Pricing Questions
Why is small-batch CNC machining so expensive per piece?
What is a reasonable minimum order quantity for CNC machining?
How can I reduce the cost of a low-volume CNC order?
Should a supplier show me how they calculated their price?
How fast can a small batch actually be produced?
We'll Show You the Arithmetic
If you're ordering 10, 40 or 200 pieces and the quotes you're getting don't make sense, send us the drawing. We'll tell you which costs are fixed and which scale, flag anything in the design that's driving setup time, and quote two quantities side by side so you can see where the numbers turn.