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When a loose bearing ruins a project mid-build, or a worn ball causes unwanted play in a mechanism, finding the exact replacement size fast is critical. Makers, hobbyists, engineers, and repair technicians who need reliable precision steel ball bearings in a wide range of diameters will find exactly what they need here — 24 sizes from 1mm to 10mm, sold in packs of 5, 10, 15, or 20 pieces.
These solid steel ball bearings are manufactured to tight tolerances for consistent roundness and surface finish. Diameters span 1mm through 10mm (approximately 0.039 in to 0.394 in), covering both metric and fractional inch equivalents such as 2.381mm (3/32"), 3.175mm (1/8"), 3.969mm (5/32"), 4.763mm (3/16"), 6.35mm (1/4"), and 7.144mm (9/32"). Material is carbon steel with a smooth, polished surface finish.
Typical use cases include replacing worn balls in skateboard or inline-skate bearings, sourcing small-diameter balls for DIY linear motion systems and drawer slides, supplying precision balls for robotics joints and RC vehicle differentials, and restocking workshop jigs that require consistent ball-detent mechanisms.
| Material | Carbon Steel |
|---|---|
| Surface Finish | Polished |
| Available Diameters | 1mm, 1.5mm, 2mm, 2.381mm, 2.5mm, 3mm, 3.175mm, 3.5mm, 3.969mm, 4mm, 4.5mm, 4.763mm, 5mm, 5.5mm, 6mm, 6.35mm, 6.5mm, 7mm, 7.144mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm |
| Diameter Range | 1mm – 10mm (approx. 0.039" – 0.394") |
| Pack Quantities | 5 / 10 / 15 / 20 pieces |
| Ball Type | Solid (non-hollow) |
| Hardness | See variant options |
| Grade / Tolerance Class | See variant options |
| Weight per Ball | See variant options |
| Product Type | Ball Bearings |
Measure the inner diameter of your bearing housing or the seat where the ball sits using a digital caliper. Match that measurement to the closest available diameter in this listing. For fractional-inch applications: 2.381mm = 3/32", 3.175mm = 1/8", 3.969mm = 5/32", 4.763mm = 3/16", 6.35mm = 1/4", 7.144mm = 9/32". If you are between two sizes, choose the smaller diameter to avoid binding.
Yes. These are solid carbon steel balls, which provide the hardness and compressive strength required for rolling-element bearing applications, ball-detent mechanisms, and light-to-medium load assemblies. They are not intended for heavy industrial press-fit bearing races under continuous high-load cycling — for those applications, confirm the grade specification with us before ordering.
Carbon steel balls can develop surface oxidation if exposed to moisture without lubrication. For indoor mechanical assemblies, applying a light machine oil or grease will protect the surface. If your application involves water exposure or humid environments, consider using the balls with a corrosion-inhibiting lubricant, or contact us to ask about stainless steel alternatives.
Standard skateboard bearings (608 type) use 3/16" (4.763mm) balls. Select the 4.763mm size in this listing to source replacement balls for that bearing type. Always verify the ball count and cage design of your specific bearing before replacing individual balls, as some bearing types are not serviceable.
Yes. Small-diameter solid steel balls are widely used in RC differential housings (commonly 3mm, 3.175mm, and 4.763mm) and in robotics joint detents and pivot mechanisms. Select the diameter that matches your differential or joint specification. The polished surface finish ensures smooth rolling with minimal friction in these applications.
Choose the 5-piece pack for a single repair where you need a few spares. The 10-piece pack suits small project builds or when replacing balls in multiple bearings of the same size. The 15- or 20-piece packs offer better per-unit value for workshop stock, prototyping runs, or projects requiring a larger quantity of the same diameter.
The balls are manufactured to consistent roundness and diameter accuracy suitable for general mechanical and DIY applications. For applications requiring a certified grade (e.g., G10, G25, G100 per ISO 3290), please contact us to confirm the grade specification before ordering.
