01The seven questions
If you only read one of these before sending a drawing, read the first. Gauge and millimetre are not the same measurement system, and mixing them on one drawing is the single most common source of a wrong part.
02Units: the one mistake worth preventing
Millimetres and inches coexist in this trade, and the conversion is not the problem — the problem is that gauge looks like a number that converts. It is not. Gauge is a numbered series, and the series differs by metal: 16 gauge stainless sheet is 1.588 mm, 16 gauge galvanised mild steel is 1.518 mm, and 16 gauge in the Birmingham series — still used for some tube — is 1.651 mm.
On top of that, a 5 mm plate has no gauge number at all. The gauge series runs out well before plate thickness, which is why a specification that mixes the two is a specification that was assembled rather than measured.
| What | We write | We do not write |
|---|---|---|
| Plate thickness | 6 mm (0.236 in) | 16 gauge |
| Length | 3000 mm | 118.1 in |
| Tolerance | ±0.05 mm at the edge | ±0.002 in |
| Temper | Ambient, stated on the sheet | — |
03Which standard governs what
Four standards come up repeatedly. Buying to the wrong one is how a plate arrives within the mill's tolerance and still does not fit.
| Subject | European | US | Governs |
|---|---|---|---|
| Stainless plate and sheet | EN 10088-2 | ASTM A240 | Composition, mechanical properties, delivery condition |
| Tolerances on flat product | EN 10051 | ASTM A480 | Thickness, width, length, flatness |
| Food contact, EU | 1935/2004 + 2023/2006 | — | Framework regulation and good manufacturing practice |
| Food contact, US | — | FDA 21 CFR | Indirect food additives and surfaces |
None of these standards describes a machined edge at ±0.05 mm. That is a fabrication tolerance, not a mill tolerance — it exists because someone machined the edge after the plate was cut, and it should be inspected as such.
04How to use this section
Each page is written to answer one question completely, with the table you would otherwise have to find in three places. Where a number depends on the application — deflection, load, alloy choice — the page gives the shape of the relationship and says plainly that it is indicative, because a real design check needs the actual geometry.
Two things are worth stating here rather than on a sub-page. Grade and thickness are independent decisions: 304 or 316L is a corrosion question, 5 mm or 10 mm is a stiffness and weight question, and neither one answers the other. And the reference data is not the quote — our lead time is 15 working days from a confirmed drawing, packing is quoted per order, and anything on these pages that looks like a promise is really a physical property you can check against your own drawing.
If a number you need is not here, ask. The answer will usually become a page, and the person who asked gets it first.
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