Grommet

A grommet is a ring — usually rubber, nylon, or metal — inserted into a hole in a panel, wall, or piece of fabric. Its job is to line the inside of the hole with a smooth, soft surface so that whatever passes through — a wire, cable, rope, or pipe — is protected from the sharp edge of the hole.

How it works

A grommet has a flared collar on both sides of a central barrel. When you press the barrel into a hole, one collar compresses and passes through. Once it emerges on the other side, it springs back to shape, locking the grommet in place. The wire or cable then passes through the smooth inner bore, protected from the sharp metal or plastic edges of the hole.

Common uses

• Electrical panels: Wires passing through holes in metal panels need grommets to prevent the insulation from being cut.
• Furniture: The round insert in a desk that lets you route power cords through the tabletop.
• Fabric and canvas: Grommets reinforce holes in curtains, tarps, sails, and flags, distributing pulling force across a wider area of fabric.
• Automotive: Cars use grommets wherever wires pass through the firewall, door panels, or body panels.

Grommet vs. ferrule vs. bushing

• A grommet lines the inside of a hole to protect wires or fabric.
• A ferrule joins, reinforces, or seals the end of a tube or handle.
• A bushing is a lining or insert that reduces friction or wear between moving parts.

The terms overlap in some contexts, but the primary function distinguishes them.

Grommet vs. eyelet

The classic identification puzzle. Both are rings that reinforce a hole in soft material, and the words are used interchangeably in craft contexts — but in practice the split is by scale and duty:

• An eyelet is small (typically under ~8 mm inner diameter), thin-stamped, and meant for thread, laces, or cord — think shoes, banners, and scrapbooking. It is set with a simple press and its flange is often decorative.
• A grommet is larger and heavier, almost always paired with a matching washer that backs the far side of the material. Tarps, sails, shower curtains, and desk cable holes use true grommets because the load is higher and the material thicker.

Rule of thumb: if it takes a hammer-and-anvil setter and carries real load, call it a grommet; if a hand press sets it and thread runs through it, an eyelet. In industrial contexts, “grommet” also covers the soft rubber or nylon sleeves that protect cable insulation — a meaning eyelets never carry.

How to size one

Grommets are quoted by inside diameter (the clear opening) and outside diameter (the flange), plus the panel thickness range they suit. For cable pass-throughs, size the ID to the connector as well as the cable: a grommet sized only to the wire forces you to cut it when you later need to pull a moulded plug through. For fabric, the hole should be cut to the grommet’s barrel diameter — too large and the flange has nothing to grip; too small and the barrel will not seat.