Your Guide to Push-In Panel Plugs, Rubber Grommets, and Nylon Caps that fit a 1 3/8" Hole
When it comes to working with a hole that measures approximately 1 3/8″ (1.375″) in diameter, whether in a panel, enclosure, machine housing or other installation, choosing the right accessory is crucial. At dangoodbuy, our collection of rubber grommets, plugs, caps and bumpers specifically engineered for the 1 3/8″ hole size ensures you can get a secure, clean and functional installation without guess-work.
Why you might have a 1 3/8″ hole opening
A 1 3/8″ diameter opening is less common than some standard sizes, yet it appears in a wide variety of scenarios including:
- Cable and conduit pass-throughs: A moderate bundle of wires or small tubing might require a larger than 1″ opening but less than 2″. A 1 3/8″ hole often accommodates this kind of medium-sized wiring harness, conduit assembly or multi-wire bundle.
- Connector or gland mounting: Certain electrical or mechanical glands, circular connectors or panel mount components are designed to fit through a 1.375″ knock-out. Once the connector is installed, you’ll want an accessory (grommet or cap) that complements that exact cut-out.
- Access or service ports: Equipment panels may include 1 3/8″ holes for service access, calibration, sensor adjustment or future expansion. When not in use, these holes should be covered to protect the interior from dust, moisture or contamination.
- Blanking and aesthetic finishing: In cabinetry, enclosures or instrumentation panels, a 1 3/8″ opening may remain as a placeholder or service point. Using a clean-fitting cap or plug improves aesthetics and prevents debris ingress.
- Vibration, spacing or buffer access: Some applications use a hole of this size for mounting a bumper or spacer that sits in or around a 1.3″ hole—helping dampen vibration or provide a buffer point.
Because 1 3/8″ is a less generic size than some (for example 1″ or 2″), it’s helpful to have a ready-made collection of accessories specifically matched to that diameter so you avoid compromise, loose fit or mis-sized parts.
What the products are used for?
Let’s examine the main categories of parts in this collection and their uses:
Rubber Grommets
A rubber grommet for a 1 3/8″ hole typically features an outer diameter slightly larger than the hole so it snaps into the panel, and an inner diameter sized for the cable, tubing or bundle passing through. These grommets:
- Protect wires/tubes from sharp panel edges, abrasion and vibration.
- Provide a finished appearance around the pass-through.
- Can absorb vibration or movement where cables or tubes pass through a panel.
Plugs & Push-In Panel Plugs
When a hole is present but not in use, a plug gives you a simple way to close it off. For a 1 3/8″ opening you’ll see plugs such as RP138. These functions include:
- Preventing dust, moisture, rodents or foreign objects from entering through the aperture.
- Providing a removable or future-serviceable seal: you can remove the plug later when needed.
- Maintaining aesthetic continuity on panels or housings.
Caps
Caps act similarly to plugs but tend to offer a smoother, more finished surface ideal for visible panels. In the 1 3/8″ collection you’ll find HPP138 in Black & White. Their uses include:
- Covering an unused hole with a low-profile finish.
- Offering a durable material (like nylon) that resists wear, UV, impact etc.
- Easily removable if the hole is needed later.
Bumpers
While less obvious for a 1 3/8″ hole size, bumpers may still apply in this context: for example, a bolt or stud or mounting point passes through a 1.3″ opening, and a bumper installed around or in the hole helps absorb impact, isolate vibration or prevent wear against the housing or panel.
Why correct sizing matters
Using a part designed specifically for a 1 3/8″ hole gives you several advantages:
- Ideal fit and retention: A part sized too small will fall out or leak; too large may deform, bulge or prevent proper seating. The collection shows outer diameters like 1.50″ or 1.75″ for 1.375″ hole parts.
- Panel thickness compatibility: Different parts in the collection specify panel thickness (e.g., 1/16″, 1/8″, 1/4″). Using the wrong thickness mismatch can result in poor retention or deforming the rubber.
- Inner diameter vs. outer diameter: For grommets, the inner diameter must match your cable/tubing; for plugs/caps, the outer diameter must provide a flush finish relative to the 1 3/8″ opening.
- Material suitability: The elastomer must resist environmental factors relevant to the application (temperature, chemicals, UV, vibration). Because the size is specific, you get parts that are optimized rather than generic “one-size-fits-all.”
- Aesthetic & functional finish: Especially for visible panels, the correct size accessory gives a professional look, avoids shifting or sagging, and ensures maintenance is simple.
How to choose the right part for your 1 3/8″ hole
Here’s a quick guide to select the correct accessory from this collection:
- Confirm the hole size: Ensure your cut-out or opening is indeed approximately 1.375″ (1 3/8″). The collection is filtered to “Fits Hole Size (in) = 1.375”. dangoodbuy
- Measure panel thickness: Check how thick the panel or wall is that the part will be installed into (e.g., 1/16″, 1/8″, 1/4″).
- Identify your need:
If routing cable/tube → choose a grommet with appropriate inner diameter.
If sealing an unused port → choose a plug or cap.
If providing buffer/dampening → consider bumper type or grommet with vibration-isolation properties.
- Choose material & color: The collection shows color options (Black, White) and materials (rubber, nylon) for different visual or environmental requirements.
- Check outer diameter or fit dimensions: For plugs or caps, ensure the outer diameter slightly exceeds the 1.375″ hole (example outer diameters 1.50″ & 1.75″). For grommets, ensure the retention lips are sized for the hole and panel thickness.
- Consider bulk/wholesale if applicable: If you’re outfitting many units or machines, utilizing bulk pricing makes sense.
Why choose dangoodbuy’s 1 3/8″ Hole Accessory Collection
Our curated collection for the 1 3/8″ hole diameter offers distinct advantages:
- Precision fit — All items are clearly labeled for 1.375″ hole size, panel thickness, inner/outer diameters and material.
- Single-source convenience — Instead of hunting through multiple suppliers, your 1 3/8″ size needs are addressed in one location.
- Industrial-grade materials & quality — Available for heavier duty applications, not just generic hardware store parts.
- Free shipping — As noted on the site, free shipping for all orders!
- Bulk & wholesale available — Important if you’re a manufacturer, systems integrator or frequent installer.
- Support & guidance — If your requirements vary (slightly thicker panel, different color, special environment), we’re here to assist.
Real-world use-case examples
- A control panel in a manufacturing line features a 1 3/8″ knockout for a data-cable gland carrying multiple sensor wires. A 1 3/8″ rubber grommet from this collection protects those wires, reduces wear and completes a clean installation.
- An enclosure in a HVAC unit has an unused 1 3/8″ access port reserved for future sensors. A push-in panel plug from the collection seals it off now, preventing dust ingress and maintaining the appearance of the cabinet.
- A vehicle or equipment interior panel contains a 1 3/8″ hole used temporarily during assembly; a nylon cap covers it after production, giving a flush finish and protecting the interior until later service.
- A custom instrumentation housing includes a 1 3/8″ diameter hole for mounting a small bumper or shock pad assembly; an appropriate bumper/grommet piece fits the hole, absorbing vibration and protecting mounts.
Installation and best-practice tips
- Ensure the hole edge is clean, deburred and free of sharp edges which might cut or damage the grommet or plug.
- Confirm the panel thickness corresponds to the specification on the product listing (many state e.g., up to 1/8″, or exactly 1/4″).
- For grommets: select the inner diameter appropriate to the cable/tubing you’re passing through to avoid excess slack or pinch.
- For plugs/caps: press fully into the hole until flush; use a gentle even pressure, and if needed a light lubricant that is compatible with the material. Our push-in panel plug will fit a panel that is 1/16" thick and our nylon locking panel plug will fit a panel thickness from 1/64" - 1/8".
- Periodically inspect installed parts, especially in harsh environments—rubber may harden, crack or degrade under high heat, UV or chemical exposure.
- Keep in mind that aesthetic finish matters: if the panel is visible, a flush cap or plug enhances the look and avoids it appearing unfinished or as a “knock-out” waiting for a part.
Final thoughts
A 1 3/8″ hole in a panel or system might seem like a small detail, but its proper finishing has significant consequences—on durability, safety, aesthetics and maintenance. By selecting the right accessory—be it a grommet, plug, cap or bumper—from the dangoodbuy 1 3/8″ hole collection, you ensure that your installation is secure, looks professional and functions as intended. Instead of selecting generic parts that may require adaptation, you’re choosing a tailored solution sized and rated for your exact diameter.
