The short answer
On a CNC bracket RFQ, **position** and **profile** tolerances are not the same quote package. Position usually locates holes or patterns to datums. Profile controls a surface (or a set of surfaces) relative to a true profile and datums. Mixing them, stacking them without a datum scheme, or painting both on every face is what widens many [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** estimate bands—not the stainless grade alone.
This guide is for buyers packaging stainless medical-adjacent brackets. Illustrations use an **Example part** only—not a customer device. Related GD&T notes live in [GD&T basics for buyers](https://3dwk.com/resources/gdt-basics-for-buyers), [GD&T callouts that raise CNC quote bands](https://3dwk.com/resources/gdandt-callouts-that-raise-cnc-quote-bands), and [datum schemes for multi-setup CNC parts](https://3dwk.com/resources/datum-schemes-for-multi-setup-cnc-parts); here we focus on **when to choose position vs profile** so estimators do not guess inspection strategy.
What position and profile mean for quoting
Position (⌀) typically controls the location of a feature of size (hole, pin, slot pattern) to datums. Profile of a surface controls how far a surface may deviate from its true profile. For quoting, also say which callouts are functional versus cosmetic. Process pages for stainless medical and related CNC ([CNC 3-axis SS 316 medical](https://3dwk.com/en/cnc-3axis/ss-316/medical.html), [CNC 5-axis SS 316 medical](https://3dwk.com/en/cnc-5axis/ss-316/medical.html), [CNC turning SS 316 medical](https://3dwk.com/en/cnc-turning/ss-316/medical.html)) assume clear GD&T notes when lots mix fastener patterns and contoured pockets.
Do not bury “tight GD&T somehow” inside a general note. Put **position on holes** and **profile on contours** explicitly, with datums named. Background: [DFM checklist before an online CNC quote](https://3dwk.com/resources/dfm-checklist-before-online-cnc-quote), [what files to send for a CNC quote](https://3dwk.com/resources/what-files-to-send-for-cnc-quote).
Datum scheme and setup cost
A clear A|B|C scheme lets shops plan probing and fixtures. Conflicting secondary datums or simultaneous requirements on every face force more setups and CMM time. Soft stock (PA66 time coeff ×0.8 under **rates.v1.1** estimates) still needs clear datums. Harder alloys (17-4PH ×1.4, IN718/IN625 ×2.5, CoCr ×2.2) amplify probing and tool-wear cost; stacked position+profile on every feature frequently auto-routes toward **needs_manual**, especially when the line mid exceeds configured planning bands (e.g. above ~$2000 for hot alloys/CoCr).
If only hole patterns matter, prefer position + ISO 2768-m on free surfaces. If a freeform pocket must mate, prefer profile with a realistic band.
Bar $/kg planning bands (estimates only): PA66 ~5, 17-4PH ~9, IN718 ~55, IN625 ~60. Stainless 316 sits in a moderate band; inspection strategy often moves the quote more than bar $/kg—see [CMM sampling plans for CNC lots](https://3dwk.com/resources/cmm-sampling-plans-for-cnc-lots) and [CMM vs optical measurement for machined parts](https://3dwk.com/resources/cmm-vs-optical-measurement-machined-parts).
Inspection method and sampling
Position patterns often suit CMM or hard gaging. Profile on complex surfaces may need scanning CMM or optical methods. Say whether FAI is full layout and production is sampling. Related: [tolerances for CNC 17-4PH what buyers specify](https://3dwk.com/resources/tolerances-cnc-17-4ph-what-buyers-specify), [surface roughness Ra for machined parts](https://3dwk.com/resources/surface-roughness-ra-for-machined-parts).
Tolerance stacking traps
Applying both tight position and tight profile to the same pocket walls without hierarchy creates ambiguous inspection. Default non-critical sizes to ISO 2768-m. Related: [how workholding changes a CNC quote](https://3dwk.com/resources/how-workholding-changes-cnc-quote), [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote).
Illustration 1 shows an **Example part** bracket with position on a 4-hole pattern versus profile on a contoured pocket wall.
Example part walkthrough
**Example part:** SS 316 bracket ~110×70×14 mm, Datum A primary face, 4× Ø6.5 holes position ⌀0.1 to A|B|C, contoured pocket profile 0.2 to A, ISO 2768-m elsewhere, Ra 1.6 on seal land only. With STEP + clear position/profile labels, expect a usable automatic planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same geometry with “all GD&T tight” often lands DFM notes or **needs_manual**—without inventing any customer PO or device cert.
Illustration 2 contrasts a vague RFQ (“precision bracket”) versus a labeled position/profile block and the clearer estimate path.
What widens bands fastest
Unlabeled mix of position and profile, missing datums, “profile everywhere” on prismatic boxes that only need hole position, and 100% CMM of every surface with no sampling plan. Quantity breaks help unit cost but do not erase inspection minutes—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost).
What to do next
Mark **position** on hole patterns and **profile** only on true contours, name datums, then upload on [quote-new.php](https://3dwk.com/quote-new.php). Service pages: [CNC machining](https://3dwk.com/cnc-machining-service.php), [materials](https://3dwk.com/materials.php). Treat **rates.v1.1** min/mid/max as estimates, not invoices. If the UI shows **needs_manual**, answer the GD&T questions rather than forcing a fake firm price.
Common questions
Can I use profile instead of position for holes?
Sometimes standards allow it, but shops usually prefer position for hole patterns. Mixing both without hierarchy widens bands.
Does tighter always mean better for medical-adjacent brackets?
No. Unnecessarily tight profile on non-mating faces raises CMM time under **rates.v1.1** estimates without improving function. Put tight callouts only where they matter.
How do hot alloys change GD&T quotes?
Probing and finishing in IN718/IN625/CoCr raise machine-time under **rates.v1.1** coeffs (×2.5 / ×2.2 estimates). Expect wider bands or manual review when every face carries a tight profile.
Should sampling plans be on the same RFQ?
Yes—pair this guide with [CMM sampling plans for CNC lots](https://3dwk.com/resources/cmm-sampling-plans-for-cnc-lots) so inspection cost is not invented later.