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When metal bearings corrode, add unwanted weight, or create electrical interference, engineers and DIY builders turn to POM plastic ball bearings as a reliable alternative. These solid polyoxymethylene rolling beads are designed for hobbyists, robotics builders, and light-machinery technicians who need dimensionally consistent, chemically resistant rolling elements without the cost or weight of stainless steel.
Each POM plastic ball bearing is machined from solid polyoxymethylene (acetal) resin — a dense, low-friction engineering thermoplastic. Available in diameters from 2 mm (approx. 0.079") to 44.45 mm (approx. 1.75"), these rolling beads cover a wide range of bore and raceway fits. Quantities range from single pieces to 1,000-piece bulk packs, making them suitable for both prototyping and production runs.
Typical use cases include 3D printer guide rails, food-safe conveyor systems where metal contamination is a concern, RC vehicle pivot points, and custom bearing housings in light automation equipment. The non-conductive nature of POM also makes these beads a go-to choice for electrical insulation applications and sensor housings.
| Material | Polyoxymethylene (POM-C / Acetal Copolymer) |
|---|---|
| Ball Type | Solid, ungrooved rolling bead |
| Diameter Range | 2 mm – 44.45 mm (approx. 0.079" – 1.750") |
| Available Sizes | 2, 3, 3.175, 3.969, 4, 4.5, 4.763, 5, 5.556, 6, 6.35, 6.95, 7, 7.144, 8, 9, 9.525, 10, 11, 12, 12.7, 14, 15, 15.875, 19, 19.05, 20, 22, 22.225, 25, 25.4, 30, 30.16, 35, 38.1, 40, 44.45 mm |
| Color / Finish | Natural white / off-white (POM natural color) |
| Surface Finish | Smooth machined surface |
| Operating Temperature | Typically –40°C to +90°C (–40°F to +194°F) |
| Hardness | See variant options |
| Tolerance Grade | See variant options |
| Quantity per Pack | 1, 5, 10, 20, 25, 50, 100, 200, 500, or 1000 pcs (see variant options) |
| Application | Custom housings, V-slot rails, open-race assemblies, light automation, robotics, food-safe conveyors |
Match the ball diameter to your housing bore or V-slot channel width. For standard imperial fits, use 3.175 mm (1/8"), 6.35 mm (1/4"), 9.525 mm (3/8"), 12.7 mm (1/2"), 19.05 mm (3/4"), 25.4 mm (1"), or 38.1 mm (1.5"). For metric fits, choose from the full metric size list. If you are unsure, contact us to confirm the correct fit for your housing dimensions.
POM (acetal) has a compressive strength of approximately 110–140 MPa — significantly lower than steel (typically 400–800 MPa). These balls are designed for light-load, low-speed applications such as guide rails, pivot points, and decorative or functional rolling elements. They are not suitable for high-load radial or axial bearing applications where steel or ceramic balls are required.
POM-C (acetal copolymer) is widely used in food-processing equipment due to its low moisture absorption, resistance to dilute acids and cleaning agents, and absence of metal contamination risk. However, food-safety compliance depends on your specific regulatory requirements. For wet environments, POM outperforms carbon steel by resisting rust and corrosion, making it a practical choice for damp or splash-prone assemblies.
These are solid rolling elements (balls), not pre-assembled bearing units. They are intended for use in custom housings, open-race assemblies, V-slot channels, or any application where individual rolling balls are required. They will not fit directly into a standard sealed bearing cartridge designed for a specific ball complement. Verify your housing geometry and ball complement count before ordering.
POM-C typically performs reliably from –40°C to +90°C (–40°F to +194°F). Prolonged exposure above 90°C can cause dimensional creep and reduced load capacity. For higher-temperature environments (above 100°C), consider PEEK or PTFE alternatives. POM maintains good dimensional stability at low temperatures, making it suitable for refrigerated or outdoor applications.
Start with a 1-piece or 5-piece pack to verify fit and performance in your prototype or housing before committing to a larger order. Once the size is confirmed, bulk packs (100, 200, 500, or 1,000 pcs) offer a lower per-unit cost and reduce reorder frequency for production runs. Bulk options are available for the most popular sizes — select your size first, then choose the quantity that matches your production volume.
No. POM is an electrical insulator with a volume resistivity typically above 10¹³ Ω·cm. This makes these balls suitable for applications requiring electrical isolation — such as PCB assembly jigs, sensor housings, and any assembly where conductive rolling elements would create a short-circuit risk. If conductivity is required, consider conductive-grade polymer or metal balls instead.
