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When a worn bearing causes wobble, noise, or premature failure in a mechanism, finding the exact replacement diameter is the real challenge. Whether you are a hobbyist rebuilding a skateboard, a technician servicing industrial equipment, or a maker prototyping a custom linear slide, having the right loose ball bearing on hand saves time and prevents costly downtime.
These loose ball bearings are manufactured from AISI 52100 chrome steel (also known as 100Cr6 or GCr15), a through-hardened bearing steel with a carbon content of approximately 1% and a chromium content of around 1.5%. Each ball is finished to G25 precision grade, meaning roundness deviation is typically within 0.63 µm (0.000025"). Diameters span from 1 mm (approx. 0.039") up to 100 mm (approx. 3.937"), with both metric and fractional imperial sizes available across the variant range.
Typical applications include replacement balls for deep-groove ball bearings, thrust bearings, and linear motion systems; load-distributing media in ball screws and ball splines; and precision rolling elements for DIY robotics, RC vehicles, and custom machinery builds requiring tight dimensional tolerances.
Roundness deviation within approximately 0.63 µm ensures consistent rolling contact and reduced vibration in precision assemblies.
Through-hardened bearing steel with high carbon and chromium content delivers excellent fatigue resistance and long service life under cyclic loading.
Available from 1 mm to 100 mm (approx. 1/8" to 4"), covering both metric and fractional imperial sizes to match a broad range of bearing housings and DIY applications.
Order in quantities from 1 piece up to 500 pieces per pack depending on the diameter selected, making it practical for both single-unit repairs and bulk restocking.
The polished chrome steel surface provides moderate corrosion resistance in dry and lightly lubricated environments; apply grease or oil for extended protection in humid conditions.
Dimensionally consistent balls can replace worn or damaged rolling elements in existing bearing assemblies without requiring housing modification.
| Material | AISI 52100 Chrome Steel (100Cr6 / GCr15) |
|---|---|
| Precision Grade | G25 |
| Diameter Range | 1 mm – 100 mm (approx. 1/8" – 4") |
| Hardness | See variant options |
| Surface Finish | Polished chrome steel |
| Roundness Deviation | ≤ 0.63 µm (G25 grade) |
| Available Quantities | 1 / 2 / 5 / 10 / 20 / 40 / 50 / 100 / 200 / 500 pcs (varies by diameter) |
| Corrosion Resistance | Moderate (dry / lightly lubricated environments) |
| Recommended Lubrication | Grease or light machine oil |
| Application | Deep-groove bearings, thrust bearings, ball screws, linear slides, DIY machinery |
Measure the inner diameter of your bearing race or housing using a digital caliper. The ball diameter should match the original specification exactly. If you are replacing balls in an existing bearing, you can also count the balls and measure one with a micrometer. Both metric (mm) and fractional imperial (e.g., 1/8", 1/4") sizes are available in the variant selector above.
G25 is a precision grade defined by ABMA (American Bearing Manufacturers Association) and ISO standards. It indicates that the roundness deviation of each ball is no greater than 0.63 µm (0.000025"). This level of precision is suitable for most industrial, automotive, and DIY applications requiring smooth, low-vibration rolling contact.
AISI 52100 chrome steel offers moderate corrosion resistance in dry or lightly lubricated environments. For applications exposed to moisture, water, or corrosive chemicals, we recommend applying a suitable grease or oil coating. If your application requires higher corrosion resistance, consider stainless steel ball bearings instead.
Yes. These loose balls are dimensionally consistent and can replace worn or damaged rolling elements in deep-groove ball bearings, thrust bearings, and similar assemblies. Simply match the diameter to your original specification. No housing modification is required as long as the diameter matches exactly.
The number of balls in a standard bearing varies by bearing size and type — typically between 6 and 20 balls per bearing. Check your bearing's original specification or count the existing balls before ordering. We offer packs from 1 piece up to 500 pieces depending on the diameter, so you can order exactly what you need or keep extras on hand for future maintenance.
AISI 52100 (also known as 100Cr6 or GCr15) is a through-hardened high-carbon, high-chromium bearing steel widely regarded as the industry standard for rolling element bearings. Its composition — approximately 1% carbon and 1.5% chromium — provides excellent hardness, fatigue resistance, and dimensional stability under cyclic loading, making it ideal for long-service-life bearing applications.
Yes. The variant range includes both metric sizes (e.g., 1 mm, 5 mm, 25 mm) and fractional imperial sizes (e.g., 1/8" = 3.175 mm, 1/4" = 6.35 mm, 1/2" = 12.7 mm, 1" = 25.4 mm, up to 4" = 101.6 mm). Select your required size from the Ball Bearing Size (Diameter) dropdown above.
