Australian purchase orders should say 1.2 mm, not “16 gauge-ish.” Gauge charts exist because imported catalogues still use them. They are a translation layer, not a specification.
The old custom-cut shop priced thickness as a first option because stiffness, weight, fold radius and parent-sheet availability all move with it. This journal does not price metal. It still treats thickness as a first-class line, because a 0.9 mm splashback and a 3 mm kickplate are not the same product wearing different adjectives.
Write millimetres. Then write the alloy, the finish, and the parent you expect. Sheet sizes and finishes are the sister pages.
Everyday millimetres
Kitchen and light fabrication work in Australia lives in a short millimetre list. Structural and plant work leaves that list and becomes plate.
| Thickness (mm) | Rough gauge (one common chart) | Typical Australian use | Notes |
|---|---|---|---|
| 0.7–0.9 | ~22–20 ga | Light covers, some appliance work | Oil-cans easily; poor as an unsupported top |
| 1.2 | ~18 ga | Splashbacks, coving, light benches on a good carcass | The everyday kitchen sheet |
| 1.5 | ~16 ga (near 1.6) | Benches, trays, many folded sections | A common step up when 1.2 drums |
| 2.0 | ~14 ga | Stiffer tops, outdoor lids, abused counters | Heavier to fold and to carry |
| 3.0 | ~11 ga | Heavy trays, kickplates, some brackets | Parent size often shrinks |
| 5.0 and up | plate, not a kitchen gauge | Base plates, structural work | You have left the kitchen shear |
Near is not a tolerance. The gauge column is a decoder for imported drawings, not a second specification. If a US drawing says 14 ga, convert to millimetres and then confirm stock.
A benchtop that drums like a biscuit tin is usually too thin for its span, not “bad stainless.” An outdoor lid in 0.9 mm 304 will oil-can in the sun. Thickness is stiffness. Span and support are the rest of the sentence.
Gauge, if you must
Different gauge systems exist (Birmingham, manufacturer charts, sheet versus wire). 16 ga is often near 1.6 mm; 18 ga near 1.2 mm; 14 ga near 2.0 mm. Those “nears” are why verbal gauges start fights on a landing.
Stainless is not always on the same gauge chart as galvanised or aluminium. If the job mixes metals, do not assume 16 ga means the same millimetre in each. The comparison page is stainless versus galvanised versus aluminium.
Write millimetres on the Australian drawing even if the architect’s detail is imperial. Convert once, in writing, and stop speaking gauge on site.
Parent sheets change with thickness
Australian merchant sheets are typically 2400 × 1200 mm, with 3000 × 1500 and 3600 × 1500 on many racks depending on gauge, grade and finish. Thinner mill 2B 304 is the easiest product to find in a long parent. Thicker No. 4 316 is not.
A 1.2 mm splashback in 3000 × 1500 is a common ask. A 3 mm No. 8 in 3600 × 1500 is a rare bird. The historic Melbourne page already said maximum sheet size depends on thickness, grade and finish. That sentence is still true.
Weight follows thickness faster than people expect. A 2400 × 1200 × 1.2 mm sheet is a respectful two-person carry. The same footprint at 3 mm is a lifting plan. At plate thicknesses you need a forklift and a different merchant bin.
Custom-cut blanks come off those parents. The old shear published ±2 mm. That tolerance does not shrink because the sheet got thicker. If anything, heavier blanks are harder to handle and easier to bruise.
Folds, welds and stiffness
Thicker sheet needs a larger internal radius and a stronger folder. The old catalogue’s smallest-leg notes get harder as thickness climbs. A 10 mm internal leg that works in 1.2 mm No. 4 may not work in 3 mm. Ask the folder. Do not scale a thin-sheet detail up with a thicker pencil.
Folded channel and folded angle are geometry-limited. A folded 1.5 mm channel is a convenience shape. It is not an engineer’s section. If the drawing treats a kitchen fold as a lintel, stop.
Welding thicker 316 is still 316, but heat input and clamp-up change. Distortion on a 1.2 mm splashback is a different problem from a 5 mm base plate. Thickness does not forgive a bad sequence.
Polish removes little metal, but it is polite to say whether the named thickness is before or after a heavy shop polish. For everyday No. 4 it rarely matters. For a ground-and-polished No. 8 edge on a thick blank, it can.
What thickness is for, by job
- Splashbacks and coving: 1.2 mm is the Australian default when the wall is flat and the carcass is there. Go up if the span is bold or the client leans on it.
- Working benches: 1.2 mm on a tight, well-fixed carcass; 1.5 mm or 2.0 mm when the top is less supported or more abused.
- Trays and lids: 1.5 mm is a common honest thickness. Outdoor lids want enough metal not to oil-can; they also want 316 if they live near salt.
- Kickplates and guards: 1.5–3.0 mm depending on the boot traffic. A 0.9 mm kickplate is a dent waiting for a trolley.
- Brackets and base plates: millimetres that have left sheet and entered plate. Specify the product.
Finish still matters. A 1.2 mm 2B liner and a 1.2 mm No. 4 bench share a thickness and not a duty. Brushed versus polished is the face argument.
How to specify it
Write the millimetre thickness, the alloy, the finish, and whether the thickness is before or after polish. Example: “316L, No. 4, 1.5 mm, 2400 × 1200 parent if needed, PVC on, grain long.”
Do not write “heavy duty.” Heavy duty is how 0.9 mm and 3 mm get into the same email. Do not write “16 gauge stainless” on an Australian purchase order and hope two merchants share a chart.
If the blank will be sheared, the historic custom-cut language still applies: ±2 mm, cut edge not extruded. Guillotine is the default. Laser and waterjet are the upgrade when the nest is intricate or the edge is seen. Cutting on site is the last resort, and a worse tolerance.
Film and handling scale with thickness only in the sense that thin polished sheet bruises if you look at it. Protecting stainless during install is the procedure page.
For the mill-floor context, use the sheet, plate and finishes hub. If the thickness question is really a fold question, the custom-cut and sections hub is the other door.