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When a worn bearing ball causes wobble, noise, or premature failure in your machinery, finding the right replacement size quickly is critical. Whether you are a home workshop enthusiast, a maintenance technician, or a small-batch manufacturer, having access to a wide diameter range in one listing saves time and reduces downtime.
These solid spheres are made from cast iron and carbon steel, offering a smooth, consistent surface finish. Diameters span from 4 mm (approx. 5/32 in) up to 120 mm (approx. 4-3/4 in), with wall thickness being the full solid cross-section — these are not hollow balls. Packing quantities range from single-piece orders up to bulk 2.8 kg bags containing thousands of small-diameter balls.
Typical applications include replacement bearing balls in drawer slides, caster wheels, and linear rail systems; load-distribution balls in jigs and fixtures; and decorative or functional spheres in DIY furniture hardware, valve seats, and grinding media for small-scale milling operations.
| Material | Cast iron / Carbon steel |
|---|---|
| Diameter Range | 4 mm – 120 mm (approx. 5/32 in – 4-3/4 in) |
| Construction | Solid (unhardened, no hollow core) |
| Surface Finish | Smooth spherical |
| Packing Options | 1 PCS / 2 PCS / 5 PCS / 10 PCS / 20 PCS / 50 PCS / 100 PCS / 2.8 KG bulk bag |
| Bulk Bag Weight | 2.8 KG per bag (small diameters only) |
| Hardness | Unhardened (standard carbon steel grade) |
| Tolerance | See variant options |
| Corrosion Resistance | See variant options |
| Common Imperial Cross-References | 3/16 in (4.76 mm), 1/4 in (6.35 mm), 1/2 in (12.7 mm), 1 in (25.4 mm) |
Measure the inner race diameter of your bearing housing or the seat diameter of your valve/caster with a caliper. Match that measurement to the closest diameter option in this listing. For imperial-sized housings, use the cross-reference column: 4.76 mm ≈ 3/16 in, 6.35 mm ≈ 1/4 in, 12.7 mm ≈ 1/2 in, 25.4 mm ≈ 1 in.
These are unhardened solid balls. They are suitable for general mechanical use, decorative applications, and grinding media in small-scale milling. If your application requires hardened bearing balls (e.g., high-load precision bearings), please check the product specifications or contact us to confirm suitability.
Cast iron and carbon steel have moderate corrosion resistance. For dry or lightly lubricated indoor environments they perform well. For wet, outdoor, or chemically exposed environments, consider applying a light oil coating or contact us about stainless steel alternatives.
Yes — the smooth spherical geometry is compatible with standard open-race ball bearing housings, caster wheel assemblies, drawer slide bearings, and valve seats. Always verify the inner race diameter of your specific housing matches the ball diameter you select.
For single repairs or prototyping, the 1 PCS or 2 PCS options are ideal. For workshop stock or small production runs, 10–50 PCS packs offer better value. The 2.8 KG bulk bags are designed for high-volume use of small-diameter balls (4 mm–6.35 mm) and contain thousands of pieces per bag.
Unhardened cast iron and carbon steel balls are commonly used as grinding media in small-scale ball mills for pigments, ceramics, and similar materials. For harder or abrasive materials, hardened steel or ceramic media may be more appropriate. Contact us if you need guidance on media selection for your specific milling application.
The 2.8 KG bulk bag is available for smaller diameters (4 mm–6.35 mm) and contains a fixed weight rather than a fixed piece count — the number of pieces varies by diameter (e.g., approximately 10,000 pcs at 4 mm, approximately 2,680 pcs at 6.35 mm). Piece-count options (1, 2, 5, 10, 20, 50, 100 PCS) are available for most diameters and give you an exact quantity.
