Eyelets and Grommets: Sizing, Compliance, and Corrosion Testing

Eyelets and grommets look like the simplest line item on a hardware BOM, but they generate a disproportionate share of quality claims after a garment ships. A hole that is off-center, a flange that lifts after two washes, or a plating layer that streaks the surrounding fabric with rust are all failures that trace back to a spec sheet that never defined the details a buyer assumed were “standard.” This guide walks through the sizing systems, material choices, compliance checks, and corrosion testing you should specify before tooling starts, along with the acceptance criteria that let you reject a bad shipment with evidence rather than opinion.

1. Eyelets vs. Grommets: Sizing and Construction

The two terms get used interchangeably in casual conversation, but they describe different constructions. An eyelet is typically a single-piece or two-piece metal ring set through a small punched hole, used where load is light and the visual profile matters — cuffs, waistbands, corset lacing, sneaker-style closures on outerwear. A grommet is a heavier two-part assembly (a barrel and a washer) crimped together through the fabric, built to survive repeated pulling — tent flaps, heavy-duty hoodie drawcords, tarps, and industrial bags.

Sizing follows a legacy gauge system inherited from the shoe and leather trades: numbers like #00, #0, #1, #2, and #3 correspond to increasing inner diameter, roughly from 3mm up to 12mm, though exact dimensions vary by tooling source. Because this numbering is not standardized across factories, specifying only “a #2 eyelet” is not enough. Your tech pack should carry the actual inner diameter, outer (flange) diameter, barrel length matched to your fabric stack thickness, and flange height after setting. Barrel length that is too short for a thick shell-plus-lining stack will not curl over fully, leaving a sharp edge exposed against skin or lining.

2. Material and Plating Choices

Functional eyelet and grommet barrels are normally drawn from ductile sheet brass, steel, or aluminum so the barrel can curl cleanly when set; die-cast zinc alloy, which holds fine detail and takes electroplating, is more often used for decorative caps and heads that sit on a separate sheet-metal part that does the clinching. Brass is chosen when the piece will be left unplated or lightly lacquered, since its own color and higher tensile strength hold up under repeated flexing at drawcord and lacing points. Stainless steel costs more per piece but resists corrosion without a plating layer at all, which matters for swimwear trims, workwear exposed to sweat and washing, and any product line where a brand wants to avoid a finish coat that can eventually chip. Natural and resin variants exist for eyelets used mostly for decoration rather than load-bearing lacing, and they avoid nickel-release concerns but not every compliance check: resin parts, and any paint or lacquer on natural materials, can still need lead testing when used on products for children.

Plating adds a second layer of decisions: nickel, black nickel, antique brass, gunmetal, and PVD finishes all behave differently under abrasion and salt exposure. A finish that looks identical to the naked eye in a sample room can perform very differently after a chamber test, which is why the finish itself — not just the base metal — needs to be locked before bulk starts. For a wider comparison of base metals across hardware categories, see our materials guide.

3. Nickel Release and REACH Considerations

Whether nickel restrictions apply to a given eyelet or grommet depends on end use, not on the part being metal. REACH Annex XVII Entry 27 restricts nickel release specifically for items intended for direct and prolonged skin contact — a waistband eyelet on a garment worn against the body is a plausible candidate for scrutiny; a grommet on the outer face of a canvas tote generally is not. Buyers selling into the EU and UK should specify nickel release testing (EN 1811, after EN 12472 wear simulation for plated or lacquered parts) on any eyelet placed at a skin-contact point, and should request the base metal composition and plating stack from the supplier rather than relying on a visual finish description. OEKO-TEX Standard 100 testing covers nickel alongside a broader substance list and is the more common request from apparel brands that want one certificate to hand to retail compliance teams rather than negotiating test scope part by part.

4. Corrosion Testing as an Acceptance Standard

Salt-spray testing under ASTM B117 or ISO 9227 is the standard method for comparing corrosion resistance between plating options, and it should appear as a numeric acceptance criterion in your tech pack rather than a vague reference to “rust resistance.” The test exposes parts to a controlled salt fog at a fixed temperature and reports the exposure duration before visible corrosion, plating blistering, or red rust appears on the base metal. For garment eyelets and grommets, 24 to 48 hours without red rust is a reasonable baseline for everyday apparel; outerwear, workwear, and marine-adjacent products often specify 72 hours or more.

Two failure modes matter separately: cosmetic corrosion, where the plating discolors or stains the surrounding fabric before the part itself fails structurally, and functional corrosion, where the barrel or flange weakens enough to pull through the fabric. A part can pass a short salt-spray window and still stain a light-colored fabric within a normal wash cycle, so pairing the corrosion test with a wash-fastness check against your actual shell fabric is worth the extra sample round, particularly on white or pastel goods.

5. Tooling, MOQ, and Sampling for Custom Eyelet Profiles

A custom flange shape, an engraved barrel face, or a nonstandard inner diameter each require dedicated tooling, which is the main cost driver on a new eyelet or grommet program. Working from an existing die library — Noraforge has over 10,000 existing mold references across eyelets, buttons, and buckle hardware — lets a buyer start from a proven barrel-and-washer combination and modify only the surface finish, avoiding a full tooling charge and the lead time that comes with it. This matters most for brands testing a new drawcord or lacing detail across a small capsule before committing it to a core line. Our how it works page walks through where tooling decisions happen in the sampling timeline.

Typical first-sample turnaround runs about 14 days from confirmed artwork and finish reference (a new mold adds 5 to 7 days before sampling starts), with color and finish consistency held to a ΔE under 1.5 between sample and bulk. MOQ starts at 2,000 pieces per design, which is workable for a single capsule collection or a first production run without forcing a brand to commit warehouse space to a color or size they have not sold yet.

6. A Typical Scenario

A typical scenario: brass eyelets with a black oxide finish on a technical jacket placket. The first samples show inconsistent flange seating, leaving visible gaps against the punched fabric hole under tension. The fix is to adjust die clearance and flange radius until the eyelets seat flush, then confirm that pull-through strength is consistent across the sample batch and meets the minimum written into the spec.

7. Building the Acceptance Checklist

Before tooling is released, a complete eyelet or grommet spec should include: base metal and plating stack named explicitly, inner and outer diameter with tolerance, barrel length matched to fabric stack thickness, flange height after setting, pull-through or burst strength minimum, corrosion test standard and required exposure hours with pass/fail definition, nickel release result where the placement calls for it, and color reference with an agreed ΔE tolerance against a physical standard rather than a digital swatch. This list becomes the basis for both the pre-production sample sign-off and the incoming inspection at bulk delivery, so disputes get resolved against numbers rather than memory of what the sample looked like. Brands sourcing eyelets alongside other trims for the same collection — buttons, rivets, or zipper pulls — should keep these specs in one document per season so finish and compliance data travel with the garment rather than living in separate email threads.

None of this adds meaningful cost to a program when it is specified up front. It becomes expensive only when it is discovered after a container has already shipped.

8. Frequently Asked Questions

What is the difference between an eyelet and a grommet?

The terms are often used interchangeably, but they usually describe different constructions: a grommet is a heavier two-part assembly of a barrel and a washer crimped together through the fabric to survive repeated pulling, while an eyelet is a lighter single-piece or two-piece metal ring set through a small punched hole where load is light and the visual profile matters. Eyelets suit cuffs and waistbands. Grommets suit tent flaps, heavy-duty hoodie drawcords, tarps, and industrial bags.

Is specifying a #2 eyelet enough for a tech pack?

No. Gauge numbers such as #00, #0, #1, #2, and #3 come from the shoe and leather trades and are not standardized across factories, so exact dimensions vary by tooling source. The tech pack should carry the actual inner diameter, outer flange diameter, barrel length matched to the fabric stack thickness, and flange height after setting. A barrel too short for a thick shell-plus-lining stack will not curl over fully.

Which eyelets need EN 1811 nickel release testing?

Buyers selling into the EU and UK should specify EN 1811 nickel release testing on any eyelet at a skin-contact point. REACH Annex XVII Entry 27 restricts nickel release for items intended for direct and prolonged skin contact, so a waistband eyelet worn against the body is a plausible candidate, while an outer-face grommet on a canvas tote generally is not.

How many salt-spray hours should garment eyelets and grommets pass?

For everyday apparel, 24 to 48 hours of ASTM B117 or ISO 9227 salt-spray exposure is a reasonable baseline, while outerwear, workwear, and marine-adjacent products often specify 72 hours or more. The test reports the exposure duration before visible corrosion or plating blistering appears, so the tech pack should state the required exposure hours and a pass or fail definition.

Can a plated eyelet pass salt-spray testing and still stain the fabric?

Yes. A part can pass a short salt-spray window and still stain a light-colored fabric within a normal wash cycle. Cosmetic corrosion, where the plating discolors or stains the surrounding fabric, is a separate failure mode from functional corrosion, where the barrel or flange weakens enough to pull through. Pairing the corrosion test with a wash-fastness check against the actual shell fabric is worthwhile, particularly on white or pastel goods.

What should an eyelet or grommet spec sheet include before tooling is released?

It should name the base metal and plating stack, inner and outer diameter with tolerance, barrel length matched to fabric stack thickness, flange height after setting, a pull-through or burst strength minimum, the corrosion test standard with required exposure hours and a pass or fail definition, the nickel release result where the placement calls for it, and a color reference with an agreed delta-E tolerance against a physical standard.