Quick Answer
There is no official conversion from emery cloth grades to sandpaper grit. The legacy grade marks on old rolls, the 3, 2, 1, 0, 2/0 and 3/0 series, predate the modern grading systems, and none of the current grit standards, FEPA 43 / ISO 6344 for coated abrasives or ANSI B74.18 for the North American CAMI scale, defines an emery grade (FEPA 43-1/43-2:2006; KB: FEPA Grit Scale). What the record supports: true mined-emery cloth was made in roughly 36 to 120 grit, 36-60 for stock removal and 80-120 for finishing (KB: Emery Flint and Natural Mineral Abrasives), and the 'emery' shop rolls sold today are almost always aluminum oxide on cloth, graded with ordinary grit numbers 60 to 400 (KB: Sanding Sheet and Roll). Buy by the printed grit number and the scale it was graded on, not by a grade name.
What emery actually is
Emery is a natural granular rock, not an engineered grain: corundum (natural aluminum oxide) with iron-bearing minerals such as magnetite, hercynite and other spinels, plus minor rutile. A typical commercial assay runs about 58 percent alumina and 25 percent iron oxide, specific gravity 3.5 to 3.8 (KB: Emery Flint and Natural Mineral Abrasives). Bulk hardness sits around Mohs 8, but that number hides a spread: the corundum phase is 9, the spinels near 8, the magnetite only 6. Being mined and graded, its composition and grain shape vary batch to batch in a way no furnace-made grain does. Naxos, in Greece, has been worked for emery for well over two thousand years, and Turkey and Greece were still the main suppliers as of 2010, at roughly 6,000 and 2,000 tonnes a year.
Emery built the coated-abrasive trade, then lost it. Silicon carbide arrived in 1891 and electric-furnace aluminum oxide followed in the early 1900s; the synthetic grains were harder, purer and batch-consistent, and displaced emery on every performance measure (KB: Emery Flint and Natural Mineral Abrasives). What keeps emery relevant is how it wears: the grain rounds off as it dulls instead of fracturing to fresh edges the way engineered grains do. That makes it a slow, ever-gentler cutter, poor at removing stock but good for final hand cleanup on steel, metal cleaning rather than shaping.
The honest grade-to-grit chart
Because emery cloth predates every standardized grit scale, old rolls carry trade grade marks instead of grit numbers (KB: Emery Flint and Natural Mineral Abrasives). No standards body has ever published an official equivalence for those legacy grades, so any grade-to-grit table online is a vendor rule of thumb, not a specification. Here is what can actually be stated with sources behind it:
| What is on the roll | Modern grit terms | Grain-size anchor | Use it for |
|---|---|---|---|
| True emery, coarse band | about 36-60 grit | ~269 microns (all major scales) | Rust, scale, heavy cleanup (historical stock-removal band) |
| True emery, fine band | about 80-120 grit | ~201 microns at 80, ~125 at 120 | Blending, pre-polish (historical finishing band) |
| Modern 'emery' shop roll (aluminum oxide on cloth) | printed grits, typically 60, 80, 100, 120, 150, 180, 220, 240, 320, 400 | ~68 microns; last point CAMI and FEPA P agree | The general metal hand-finishing ladder |
| Legacy grade marks: 3, 2, 1, 0, 2/0, 3/0 | no official equivalence in FEPA, ISO or CAMI | none defined | Old stock; test on scrap first |
| Crocus cloth (iron-oxide polishing grain) | below the standard scales; graded ultra-fine | below the FEPA/CAMI ladder | Final scratch-free polish on soft metals |
Table sources: the 36-120 working range and crocus (KB: Emery Flint and Natural Mineral Abrasives), shop-roll grits (KB: Sanding Sheet and Roll), micron anchors and the 220-grit agreement point (KB: Grit Conversion Chart), crocus below the scales (KB: Abrasive Cord and Tape).
Two buying rules follow. First, when a roll prints a real grit number, check the scale: a P prefix means FEPA grading, a bare number sold in North America usually means CAMI, and the two only track each other to about 220 grit before diverging, as we cover in FEPA vs CAMI grit scales and the full abrasive grit chart. By the fine end the gap is roughly double: a CAMI 400 grain is about 23 microns against a FEPA P400 grain's 35 microns, so the same number is a different abrasive (KB: FEPA Grit Scale). Second, when a roll carries only a legacy grade name, treat the grit as unknown: run it on a scrap offcut and slot it in by behaviour, not folklore.
Grit, micron and finish on metal
What you care about at the machine is the finish a grit leaves. These are typical outcomes for coated abrasive on metal, not guaranteed; substrate, pressure, lubrication and backing all move the result (KB: Grit Conversion Chart).
| Grit on the roll | Grain size (approx. microns) | Typical Ra | What it leaves |
|---|---|---|---|
| 80 | ~190-201 | ~1.8 um (~71 uin) | Visible scratch; cleanup and shaping |
| 120 | ~125 | ~1.3 um (~52 uin) | Uniform brushed look |
| 220 | ~68 | ~0.45-0.5 um (~18-19 uin) | Smooth to the touch |
| 320 | ~36-46 (scale-dependent) | ~0.3-0.4 um (~12-16 uin) | Fine pre-polish |
| 400 | ~23 CAMI / ~35 FEPA P400 | ~0.25-0.35 um (~10-14 uin) | Near-polish; state the scale or the number is meaningless |
The Ra figures are process-dependent approximations (KB: Grit Conversion Chart). If you are chasing a specified roughness rather than a look, work from our grit to surface finish Ra chart and verify with a gauge: a grain micron and a finish Ra micron are different quantities that share a unit.
Where cloth-backed emery still wins at the lathe
Why a shop roll lives in the tailstock drawer of nearly every manual lathe is the backing, not the grain. Emery cloth and its aluminum-oxide successors are sold as shop rolls in 1, 1-1/2 and 2 inch widths on 50-yard dispenser spools, on flexible J-weight or general-purpose X-weight cotton cloth (KB: Sanding Sheet and Roll). That construction buys three things paper cannot (KB: Cloth Backing):
| Property | Cloth-backed roll | Paper-backed sheet |
|---|---|---|
| Tensile and tear strength | High | Low to medium |
| Heat and tension tolerance | High | Low |
| Flexibility | Tunable; J-weight conforms without cracking | Limited |
| Cost | Higher | Lowest |
Held as a strip against turning work, the abrasive is loaded in pure tension while friction heats it, exactly the loading a J or X cotton cloth is woven for and where a paper sheet tears or scorches. The same properties carry over to hand deburring, rust removal and polishing pipe and contoured metal no power-tool disc can reach (KB: Sanding Sheet and Roll). The emery grain earns its keep too: rounding over instead of resharpening, a worn strip gets gentler, useful when sneaking up on a fit rather than removing stock. For the last step on soft metals, crocus cloth sits below the grit scale entirely and polishes without scratching (KB: Abrasive Cord and Tape).
Work through the grits in order, 120, 220, 320, 400, rather than leaning harder on one strip. Keep the strip short, hold an end lightly in each hand, and never wrap it around the spinning work or your fingers. If the geometry suits a machine, a flap wheel does the same contour-following, cloth-backed finishing on pipes and tubes, and a cloth-backed sanding belt covers the broad flats.
The silica footnote: why the grain matters for your lungs
Emery has one quiet advantage over the cheapest legacy sheet: chemistry. It is alumina plus iron oxides, no crystalline-silica flag, while flint paper is crushed quartz and tripoli powder is microcrystalline quartz, both of which generate respirable crystalline silica dust as they break down. That dust is regulated: the OSHA permissible exposure limit is 50 micrograms per cubic metre of respirable crystalline silica as an 8-hour average, with an action level of 25 (29 CFR 1910.1053; KB: Emery Flint and Natural Mineral Abrasives). Synthetic aluminum oxide and silicon carbide sidestep the hazard the same way; our guide to aluminum oxide vs silicon carbide covers which grain suits which metal. Whatever the grain, sanding dust is still dust: the silica point is a reason to leave flint paper on the shelf, not to skip extraction.
What to reach for today
Genuine mined emery is now a legacy specialty; most rolls labelled emery are aluminum oxide on cloth, and honest suppliers say so on the label (KB: Sanding Sheet and Roll). For the jobs emery cloth historically owned, the modern stocklist is a cloth shop roll in 120-400 grit for lathe and hand polishing, flap wheels for deburring and blending contours under power, belts for flats, and a non-woven polishing wheel where you want a finish without a directional scratch. As a stocking supplier we would rather tell you which grain and grit is on the product than lean on a hundred-year-old grade name; if a spec matters to your part, ask and we will pull the sheet.
FAQ
What grit is emery cloth equivalent to?
No single equivalent. True mined-emery cloth ran roughly 36 to 120 grit, 36-60 for stock removal and 80-120 for finishing (KB: Emery Flint and Natural Mineral Abrasives). Modern rolls sold as emery are usually aluminum oxide graded 60 to 400; trust the printed number.
Are old emery grades like 0, 2/0 and 3/0 an official standard?
No. Those marks predate the modern grit systems, and none of the current standards, FEPA 43 / ISO 6344 or ANSI B74.18 (CAMI), defines an emery grade or an official equivalence (KB: FEPA Grit Scale). Published conversion tables are vendor rules of thumb; test old stock on scrap first.
Is modern emery cloth made from real emery?
Usually not. Real emery is a mined corundum-and-iron-oxide rock, historically from Naxos and Turkey; most cloth sold as emery today carries synthetic aluminum oxide instead, harder and far more consistent (KB: Emery Flint and Natural Mineral Abrasives; KB: Sanding Sheet and Roll).
Why does emery cloth work better than sandpaper on metal?
The backing. Cloth has high tensile and tear strength and high heat and tension tolerance where paper is low on both, and flexible J-weight conforms to round work without cracking (KB: Cloth Backing). Strip-polishing loads the abrasive in tension, which cloth is built for and paper is not.
Does emery cloth dust contain crystalline silica?
Emery itself is alumina plus iron oxides, no crystalline-silica flag. The silica hazard belongs to flint (quartz) paper and tripoli powder, whose dust falls under the OSHA respirable crystalline silica rule, permissible exposure limit 50 micrograms per cubic metre (29 CFR 1910.1053; KB: Emery Flint and Natural Mineral Abrasives).
Can I polish work on a lathe with emery cloth?
Hand-polishing turning work with a cloth strip is emery's surviving trade niche. Step through the grits, keep the strip short and free to pull away, and never wrap it around the spinning work or your fingers. Finish soft metals with crocus cloth (KB: Abrasive Cord and Tape).