State tolerances as conditional claims tied to the process, the feature, the size range, and the material, and have the people who actually hold them approve every number. List materials by the grades and forms your plant runs, and say plainly what you outsource or decline. An engineer screening suppliers can then check fit in a minute instead of sending an RFQ to find out.
Material and tolerance are often the first two filters an engineer applies to a supplier list. Yet a manufacturing site may answer both with one line, such as "we work in all common metals and hold tight tolerances," which gives the engineer nothing to check and an assistant nothing specific to repeat. The fix is not a longer adjective. It is a set of statements your engineering and quality teams would sign.
This is a content-planning question for manufacturers, not engineering advice. Your engineering and quality staff own every capability number on the site, and nothing here suggests what a design should call out.
A tolerance means nothing without its conditions
Whether a shop can hold a given tolerance depends on the process, the feature type, the size of the part, the material, and how the feature is inspected. A best-ever result on one part is not a tolerance you hold in production. When a site states a single number with no conditions, the engineer has to guess which features it applies to, and an assistant summarizing the page has no way to carry the missing conditions along.
| Vague claim | Conditional version (fictional figures) |
|---|---|
| We hold tight tolerances. | On turned diameters up to the size range engineering approves, in free-machining stainless, we hold the band stated on our capability sheet, verified by in-process gauging and final CMM inspection. |
| Precision sheet metal. | Formed parts in cold-rolled steel up to the stated thickness, with bend tolerances by flange length listed in the table below. |
| All common metals. | Aluminum, carbon steel, and the stainless grades listed below, in bar, plate, and sheet. Titanium by quote only. |
| Tight-tolerance grinding. | Surface and OD grinding for hardened steel parts within the size envelope listed, with the flatness and roundness figures quality has approved. |
General tolerances and feature callouts are different claims
Drawings often leave many dimensions without an individual tolerance and rely on a general tolerance note. ISO 2768-1, titled "General tolerances, Part 1: Tolerances for linear and angular dimensions without individual tolerance indications," says it is "intended to simplify drawing indications and specifies general tolerances in four tolerance classes." Its scope covers "workpieces that are produced by metal removal or are formed from sheet metal," and as of October 2026 ISO lists the 1989 edition as due to be revised, so have engineering confirm the current edition before a page names it. If your engineering team routinely quotes against a general tolerance standard when a print does not specify, a sentence saying so, and naming the standard and class, tells an engineer something useful about how you read their drawing.
Experience with a material deserves the same honesty. A grade your plant runs every week and a grade it ran once for a single job are different claims, even if both technically belong on a list. Consider marking the materials you run routinely and noting which others you will quote after review. An engineer with an unusual alloy learns more from "quoted case by case, with a test cut if needed" than from seeing it buried in a long list.
That statement is separate from the tight callouts on critical features, which belong on the capability page with their own conditions. Keeping the two apart stops a buyer from reading a general tolerance as your best capability, or your best capability as something you hold on every dimension.
Writing the materials list
Name materials the way they appear on purchase orders and prints: the alloy or grade, the form (bar, plate, sheet, tube, casting, forging), and the condition where it matters, such as annealed or heat treated. Say which materials you stock, which you buy per job, and which the customer supplies. List the secondary processes you perform in house and those you send out, such as heat treat, plating, anodizing, or passivation, so the buyer knows where the part leaves your control.
The decline list deserves equal care. Before writing it, ask your estimator one question: "Which material requests do we no-quote, and what is the reason each time?" A page that says the shop does not machine beryllium copper, or takes plastics only for low-volume prototypes, saves both sides a quote cycle. Ask quality as well what material documentation you supply with shipments, and describe it in their words.
A fictional materials and tolerance section
Here is a hypothetical example for a fictional precision sheet metal fabricator in Georgia. The figures are left to the shop's engineering team on purpose, and it describes no real company.
The section opens: "We laser cut, punch, form, and weld carbon steel, stainless, and aluminum sheet within the thickness ranges shown below. We do not form titanium or work with coated stock thicker than our press brake tooling allows." A table follows, listing each process, material, thickness range, and the tolerance the shop holds for that process, each approved by the engineering manager. A short paragraph explains that bend tolerances widen as flange length grows and that tighter requirements are reviewed at quote. The section closes by stating which finishes are applied in house and which go to an outside finisher the shop qualifies.
Another short table gives the largest flat blank and the largest formed part the shop can handle, so a buyer with an oversized enclosure knows before quoting whether the part fits the equipment. An engineer can read that and know in under a minute whether to send a print. The paragraph also gives an assistant a set of plain sentences it could quote without losing the conditions.
Keeping the numbers honest
Capability changes when equipment changes, when a key machinist retires, or when a process moves to another cell. Give the materials and tolerance section an owner in engineering and a review trigger tied to those events. When a figure changes, update the spec sheets and quote templates at the same time, so a buyer does not find one number on the site and another on the quote. Nobody writing the page should be estimating what your inspection equipment can verify; the quality lead knows, and the page should say what they say.
Hudson South's process starts there. The Authority Asset collects capability sheets, inspection procedures, and approved figures from the people who own them. Hudson Twenty-One records how your engineers communicate across 21 dimensions, including the units and terms they use. Market Intelligence researches the material and tolerance questions buyers ask in your sector, and AEO Creation writes answer-first sections that keep every condition attached. Related pages cover capability pages beyond an equipment list and the full manufacturing and industrial overview.
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- ISO 2768-1:1989, General tolerances, Part 1: Tolerances for linear and angular dimensions without individual tolerance indications. International Organization for Standardization. Read 2026-10-16.