The short answer
On pocketed plate and housing RFQs, a **minimum uncut web between adjacent CNC pockets** is not the same note as pocket depth, a [corner radius](https://3dwk.com/resources/pocket-corner-radius-dfm-cnc-buyers), or a general “thin walls OK” cloud. The web is the remaining parent material between two pocket or slot walls—measured after both pockets, any floor steps, and any through-slots are cut—not the distance you see between pocket outlines on a mid-plane screenshot. Silence on that leftover width, on whether the web is also a clamp or cosmetic face, and on whether a slight bulge or witness is allowed, is what widens many [quote-new.php](https://3dwk.com/quote-new.php) **rates.v1.1** estimate bands—not the extra minutes of floor milling alone.
This guide is for buyers packaging aluminum pocket RFQs where CAD shows two pockets or a pocket-and-slot pair with only 1–3 mm of leftover wall and no named minimum web. Illustrations use an **Example part** only—not a customer housing. Sibling notes live in [CNC pockets, thin walls and undercuts](https://3dwk.com/resources/cnc-pockets-thin-walls-undercuts) and [minimum wall CNC vs SLM](https://3dwk.com/resources/minimum-wall-cnc-vs-slm-for-buyers); here we focus on **adjacent-pocket web packaging** so estimators do not have to guess whether a 1.5 mm leftover rib is structural, cosmetic, or accidental.
What an uncut web means for quoting
An **uncut web** is the shortest material path that remains between two finished pocket or slot walls. It is not the same as a floor thickness to the opposite face, and a general wall-thickness note does not automatically protect a rib that only appears after a second pocket is opened. A web that looks comfortable in a top view can still be a knife-edge after a side mill or a stepped floor. Process pages for electronics-thermal aluminum ([CNC 3-axis Al 6061 electronics-thermal](https://3dwk.com/en/cnc-3axis/al-6061/electronics-thermal.html), [CNC 5-axis Al 6061 electronics-thermal](https://3dwk.com/en/cnc-5axis/al-6061/electronics-thermal.html), [CNC 3-axis Al 6061](https://3dwk.com/en/cnc-3axis/al-6061.html)) assume leftover-web and clamp notes when lots mix open pockets with narrow ribs.
Do not bury “leave the rib, use best judgment” inside a notes cloud. Put **POCKET A / POCKET B, MIN UNCUT WEB 2.5 AFTER BOTH FLOORS, CLAMP NOT ON WEB** on the PDF and mirror it in RFQ text. 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), [deep pockets and tool reach](https://3dwk.com/resources/deep-pockets-and-tool-reach-cnc-quotes).
Depth, tool diameter, and leftover ribs
Two shallow 4 mm pockets with a 3 mm web are not the same risk as two 18 mm pockets with the same leftover width. Tool deflection and wall push-off grow with depth-to-web ratio; a named corner radius that is smaller than half the web can also leave a cusp that is thinner than the drawing implies. Measure the web **after** both floors and any through-features, not only from the blank outline. [Plate vs billet stock](https://3dwk.com/resources/plate-vs-billet-stock-cnc-aluminum) can change how a web sits relative to a sawn or rolled face, but it does not replace a written minimum.
Aluminum 6061 plate $/kg planning bands sit in the mid-commodity range under **rates.v1.1** material tables; material cost is rarely the web story—chatter, break-through, and clamp placement are.
Clamps, bosses, and cosmetic webs
Name where a vise or clamp may land if the leftover rib is also the only gripping land, and say whether the web is a cosmetic A-side or may show a tool witness. A [boss or rib](https://3dwk.com/resources/designing-bosses-and-ribs-for-cnc-housings) that blends into a thin web should show the leftover width in one view after the blend. Asking “just leave 2 mm” in email, without updating CAD, leaves two conflicting packs.
Tolerance and inspection traps
Calling “do not break through” without a remaining-web value, mixing a 1 mm web with a tight floor flatness, or asking for 100% optical check of every cosmetic rib, all force **needs_manual**. Default non-critical pocket floors to ISO 2768-m and put a functional minimum web only on thin ribs or clamp-load walls. Related: [ISO 2768 general tolerances on CNC RFQs](https://3dwk.com/resources/iso-2768-general-tolerances-cnc-rfq), [flatness vs parallelism on CNC plates](https://3dwk.com/resources/flatness-vs-parallelism-callouts-cnc-plates).
Illustration 1 shows an **Example part** plate with a labeled 2.5 mm uncut web between two open pockets versus a thinner 1.2 mm rib next to a through-slot on the same blank.
Example part walkthrough
**Example part:** Aluminum 6061-T6 plate ~150×100×12 mm, two 8 mm-deep pockets with a 2.5 mm minimum uncut web after both floors, one through-slot with a 3.0 mm remaining wall to pocket A, ISO 2768-m general. With STEP + **POCKET A/B MIN UNCUT WEB 2.5 AFTER BOTH FLOORS; SLOT TO POCKET A MIN WALL 3.0; CLAMP OK ON FACE A RAILS, NOT ON WEB**, expect a usable automatic planning band on [quote-new.php](https://3dwk.com/quote-new.php). Same geometry with silent CAD and “leave the ribs as needed” often lands DFM notes or **needs_manual**—without inventing any customer PO.
Illustration 2 contrasts a vague RFQ (“keep the walls thin, do not break through”) versus a labeled web pack and the clearer estimate path.
What widens bands fastest
Unlabeled mix of shallow and deep pockets sharing one leftover rib, webs that appear only after a second floor is cut, clamp lands left unspoken, and 100% cosmetic inspection of every thin wall. Quantity breaks help unit minutes but do not erase web ambiguity—see [how quantity breaks change CNC unit cost](https://3dwk.com/resources/how-quantity-breaks-change-cnc-unit-cost) and [what needs_manual means](https://3dwk.com/resources/what-needs-manual-means-preliminary-quote).
What to do next
Mark each functional leftover rib with a **minimum uncut web** (after both pockets, floors, and slots), 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 remaining-web questions rather than forcing a fake price.
Common questions
Is 2 mm always enough web in aluminum plate?
Not as a silent default under **rates.v1.1** estimates. 2–3 mm is a common starting point for shallow open pockets in 6061, but deeper pockets, tight corner radii, cosmetic ribs, and clamp-load walls may need more leftover width or a revised pocket layout. Write the web you actually need.
Can I write “do not break through” and leave the model as-is?
Only if the leftover web is already obvious and generous in every view. A 1.2 mm rib between two 12 mm-deep pockets is not rescued by a notes cloud. Update CAD or add a minimum web so the shop and the estimate see the same intent.
When should I merge two pockets instead of tightening the web note?
When the leftover rib is too thin to mill without chatter or breakthrough, when the same strip is the only clamp land, or when the web has no structural or sealing job. Merging the pockets, adding a thicker rib, or [splitting the part](https://3dwk.com/resources/when-to-split-a-cnc-part-into-two-pieces) is cleaner than asking the shop to “be careful.”
How should I call out a boss that sits on a thin web?
Show the leftover width **after** the boss blend, and say whether the boss face or the web is the cosmetic side. Leaving only a boss-height note leaves the estimator guessing whether a 2 mm web under a tall boss is intentional.