Twice this month a purchasing manager forwarded me two quotes for the same part and asked which shop was lying. Neither was. One quote came in at 18.40 USD and the other at 27.90, same 6082-T6 bracket, same 200 pieces, same drawing revision. The gap sat almost entirely in two lines that neither quote bothered to explain: how the stock was bought, and how many setups the shop had budgeted for.
That is the real problem with comparing CNC quotes. The bottom number is a summary of five decisions. Most quotes show you the summary and hide the decisions. Here is what those five lines are, what a fair one looks like, and where the money actually goes.
Material: the line everyone checks and nobody reads
Buyers anchor on material because it is the only line that feels verifiable. It is also rarely the reason one quote beats another. On an aluminium bracket at 200 pieces, material usually lands somewhere between 15 and 30 percent of the part price. On a small stainless fitting it can climb past 40 percent.
What matters is not the alloy alone but the form it arrives in. As a budget estimate, 6061-T6 plate runs somewhere around 5 to 7 USD per kilogram in our region, and 7075-T6 lands at roughly two and a half to three times that. Those are estimates for planning, not firm prices. But the bigger swing is buy-to-size versus cut-from-plate. If your part fits a standard plate width, we nest it and you pay for the material you use. If the geometry forces a 60 mm thick block to be hogged down to an 18 mm wall, you are buying a lot of aluminium that ends up as chips, and the quote will show it.
If you want a first pass on what your alloy and stock form imply, the materials page lists what we keep on the floor and what we order in.
Setup: the line that quietly scales with quantity
Setup is one-time work. It does not get cheaper because the part is simple, and it does not scale with the order. That single fact explains most quote gaps at low volume.
A part we can hold in soft jaws is roughly one to two hours of setup. A part with an awkward datum, a thin wall, or five faces to reach is a dedicated fixture, and that is six to twenty hours before a chip is cut. On five pieces, twenty hours of fixturing spread across five parts is four hours of labour per part. On five hundred pieces it is two and a half minutes. Same fixture, same quote line, completely different meaning.
So when you compare two quotes at 10 pieces, ask what fixture each shop assumed. A cheap quote that assumed soft jaws and a re-clamp per face will come back with a first-article problem, and you will pay for it in schedule instead of on the invoice.
Cycle time: the line that hides the real story
Cycle time is where a quote earns or loses its credibility, because it depends on how much metal has to leave the block. A part with 70 percent material removal is not the same job as a part with 20 percent, even when the finished geometry looks similar in the PDF.
We ran a 200-piece run of a 6061 sensor housing last quarter. Finished weight 180 grams, starting block 1.1 kilograms. Cycle time settled at 22 minutes per part on a three-axis VMC, plus a 4-minute second op. A shop quoting 12 minutes for that part is either planning to run a much more aggressive toolpath than the wall thickness safely allows, or has not looked at the drawing closely.
Machine rates are the multiplier here. As a budget estimate, a three-axis VMC with a 1000 x 500 x 500 envelope runs about 45 to 60 USD per hour in our region, a 3+2 trunnion machine 70 to 90, and simultaneous five-axis 110 to 160. Again, estimates for planning. If a quote shows a low cycle time on a high-removal part, the missing minutes will reappear as a first-article rejection or a hand-finishing charge.
Tolerance and inspection: the silent multiplier
General tolerances cost nothing extra. Tight ones cost a lot, and they cost it in ways that do not show up until you read the inspection line.
Going from a general plus-minus 0.1 mm to a plus-minus 0.02 mm true position usually means slower feed rates, more frequent tool changes, temperature-controlled finishing passes, and a CMM report on every batch rather than a sample. On a small part that can double the price. The tolerance chart shows what each process realistically holds and what tightening actually costs, which is a faster way to answer the question than arguing about it after the fact.
The practical rule: put a tight tolerance only on the features that function. A 0.02 mm callout on a decorative edge is money you will never get back.
Finishing and treatment: cost plus calendar
Finishing is usually subcontracted, which means it carries two penalties. It adds cost, and it adds days. As a budget estimate, clear Type II anodising on a small aluminium part runs around 1.20 to 2.00 USD per piece at 200 pieces. Bead blasting is cheaper. Passivation on stainless is a modest per-part charge but often a three to five business day addition to the lead time, because it moves to another facility.
What buyers miss is that finishing rarely travels alone. Anodise plus laser marking plus a masked area is three operations in two shops, and the lead time compounds. If your schedule is tight, the honest move is to ask which finishes can be dropped or deferred to a second order.
What a quote should actually tell you
A quote you can act on names the alloy and stock form, states the quantity each price is based on, separates one-time setup from per-part cost, gives a cycle time, lists the finishes and the inspection level, and states a lead time measured from drawing approval rather than from today. If a quote omits the setup line, you cannot tell whether it is cheap or just incomplete.
When you send us a drawing we return a breakdown along those lines rather than a single number, because a single number is not comparable to anything. For a fast first look at budget, put the model through the instant quote tool and use the number as a planning figure. Our capabilities page lists the machines on the floor and their envelopes if you need to check whether your part fits our standard work.
For a firm number, send the STEP file with the 2D drawing that carries the tolerances, the quantity, and any finish and inspection requirements. Contact our team and we confirm within 1 business day.