The Information a Stainless Shop Needs to Quote You
September 21, 2026
Three quotes on an incomplete drawing are three different scopes. This is the list that makes them the same scope.
On the drawing
1. Material, grade and condition. Not stainless. Not even 17-4 PH. Write 316L per ASTM A276, or 17-4 PH H1075. If you genuinely do not know, write the environment instead and say the grade is open. See the buyer guide.
2. General tolerance. One note, typically ±0.1 mm or a standard such as ISO 2768-m.
3. Tight tolerances, individually, only on features that mate. Marked on those dimensions, not in the title block. What each decimal place costs.
4. Datums that reflect how the part is used, and that still exist after any welding, ageing or grinding.
5. Surface finish. A general note plus symbols on the surfaces that matter, with the unit stated. Ra 0.8 micrometre and 32 microinch are the same thing and a drawing that mixes them causes errors. Surface finish guide.
6. Passivation or electropolishing, with the standard and the test. Passivate per ASTM A967 citric Method 1, test per copper sulphate, certificate required. Not the word passivate. Citric against nitric.
7. Threads with size, pitch, class, depth of full thread and blind or through. Threading stainless.
8. Edge condition. Break all sharp edges 0.2 to 0.4 mm is a normal note. On food contact parts, say which internal radii are required.
9. Marking. Part number, revision, heat number, method and location. Laser marking and electrochemical etching behave differently on a passivated surface, so say which is acceptable.
In the RFQ email or form
These rarely fit on a drawing and they change the price as much as anything on it.
10. Quantity now, and whether it repeats. With honest uncertainty attached. Prototype against production.
11. Where the part lives. One sentence. Washed down daily with 2 percent caustic at 70 C. Immersed in sea water. Sealed dry enclosure. This single sentence lets a shop tell you the grade is wrong before the parts are made.
12. What it mates with, and whether anything slides against it. Galling risk is invisible on a drawing. Nitronic 60 and galling.
13. Whether the part will be welded, by you or by anyone downstream. This decides L grade or not. Machining stainless weldments.
14. Certificates you need back. Mill cert with heat number, passivation certificate, first article report, CMM report, material test report. List them. Each one is office hours.
15. Inspection scope. Which features get measured and reported. A full report on 40 dimensions and a report on the 6 critical ones are very different prices and tell you much the same thing.
16. Industry and any quality system requirement. Medical, food, aerospace, pressure equipment. ISO 13485 against ISO 9001.
17. Delivery date, and whether it is firm. As soon as possible is not a date. If you have a real deadline, say it, because a shop may quote a different route to hit it.
18. Packaging and shipping. Individually wrapped, cleaned and bagged, vacuum sealed, palletised. Medical and food parts often need more than a box. Say the Incoterm if you are shipping across a border.
19. NDA, if your drawing is sensitive. Ask before you send files, not after.
What not to do
Do not send only a STEP file. Geometry without tolerances, material and finish is not a specification, and every shop will fill the gaps differently.
Do not write the tightest number you can think of. A blanket ±0.02 mm and a global Ra 0.8 micrometre note are the two most expensive habits in machining, and both are usually accidental.
Do not leave passivation as one word. It is the single most common source of quote variance on stainless parts.
Do not hide the quantity. Understating to get a low unit price does not work, because the price will not scale the way you hoped when the real order arrives.
Do not ask ten shops. Your drawing is intellectual property and a wide blast does not get better prices, it gets less attention from each shop. Three serious quotes beat ten indifferent ones.
A workable template
Part: 316L valve body, 90 x 60 x 45 mm Material: 316L per ASTM A276, dual certified acceptable, mill cert with heat number required Quantity: 180 now, expecting twice a year at similar volume Tolerances: ISO 2768-m general, ±0.02 mm on the seat bore only, marked on the drawing Finish: Ra 1.6 micrometre general, Ra 0.8 micrometre on internal product contact surfaces Passivation: ASTM A967 citric Method 1, copper sulphate test, certificate required Environment: clean in place daily, 2 percent caustic at 70 C Welded: no, but a fitting is welded on by us at assembly Inspection: first article with the 6 dimensions marked critical Needed by: 6 weeks from order, firm Files: STEP plus PDF drawing attached NDA: not required
Every shop quoting that is quoting the same part. That is the entire point.
What we do with it
We read the RFQ, check whether anything important is missing and come back within 24 business hours either with matched shops or with the questions that have to be answered first. Then up to three shops that already cut these grades quote you directly, and you deal with them. Send yours here, or look at how to vet the shops that come back.
Frequently asked questions
Do I need a full drawing, or is a STEP file enough?
A STEP file alone cannot carry tolerances, surface finish, material, passivation or inspection requirements. Send both. The STEP file gives the geometry and the PDF drawing gives everything a shop has to price.
Should I tell shops my target price?
It helps more than it hurts. A shop that knows your target can tell you which requirement is blocking it, and that conversation is usually worth more than a small discount on an unchanged part.
What if I do not know the answer to some of these?
Say so rather than guessing. Not sure is useful information. A guessed tolerance or a guessed grade gets quoted as if it were firm, and you pay for it.
Need a quote for this part?
Send the drawing. We match you with up to 3 stainless shops and reply within 24 business hours.
Get matched with a stainless shopFigures in this guide are published specification limits or published typical values for the alloy, not measurements of any part. Machinability is rated against free-machining carbon steel B1112 at 100 and PREN is chromium plus 3.3 times molybdenum plus 16 times nitrogen. The conventions are set out in thereference section and the editorial standards.