Buy Miniature Ball Bearings Online in Australia
Miniature ball bearings are precision small-bore bearings — typically 3 mm to 12 mm bore — used in instruments, robotics, RC equipment, dental handpieces, optics, model engineering, fishing reels, and electronics. They're not just "smaller versions" of standard bearings — they're built to higher precision grades, with tighter dimensional tolerances and smoother running than industrial-grade bearings. AIMS stocks the EZO miniature range across the 620, 630, 680, 690, 6200, 6300 and 6900 series, in both metric and inch sizes, with metal shields (ZZ), rubber seals (2RS) and open configurations.
Miniature Bearing Size Reference
Miniature bearing part numbers follow a consistent pattern — the first digit indicates the series, the last two digits indicate the bore size (in mm for metric numbering).
| Series | Bore range | Typical use |
|---|---|---|
| 620 | 3 mm – 12 mm | Standard miniature general-purpose |
| 630 | 4 mm – 12 mm | Heavier radial load miniature |
| 680 | 3 mm – 12 mm | Instrument precision (extra-light series) |
| 690 | 3 mm – 12 mm | Thin-section miniature |
| 6200 / 6300 | 10 mm – 25 mm | Small-frame general-purpose (deep groove) |
| 6900 | 10 mm – 25 mm | Thin-section small-frame |
Worked example: 608 = 600-series, 8 mm bore, used in skateboard wheels, 3D printer carriages, RC car wheels. 6200 = 6200-series, 10 mm bore, commonly found in small motors and pumps.
Open vs Shielded (ZZ) vs Sealed (2RS) — Miniature Variants
- Open — no closure. Use for instruments where you want minimum friction and where contamination is controlled externally. Common in dental handpieces (lubricated externally) and clean-room optics.
- Shielded (ZZ) — metal shields press-fitted to inner race. Lower friction than 2RS. Good for clean dry indoor environments and instruments. Most common closure for skateboard, RC and 3D printer use.
- Sealed (2RS) — rubber contact seals. Higher friction but vastly better contaminant exclusion. Use for outdoor RC, fishing reels exposed to salt water, and any wet or dusty environment.
Precision Grades — When ABEC Matters
Miniature bearings are graded by ABEC class (or ISO P-class equivalent). Higher class = tighter tolerances and smoother running, but also higher cost.
| ABEC class | ISO equivalent | Use case |
|---|---|---|
| ABEC-1 | P0 | General-purpose industrial — most off-the-shelf miniatures |
| ABEC-3 | P6 | Better-quality skateboard, RC, general precision |
| ABEC-5 | P5 | High-speed RC, fishing reel premium, instrument grade |
| ABEC-7 | P4 | Dental handpieces, high-precision optics, lab equipment |
For most applications, ABEC-1 or ABEC-3 is plenty. ABEC-7 is overkill for skateboards regardless of marketing claims — the gains only show at very high RPM with precise loads.
Applications
- RC vehicles — cars, drones, helicopters, planes
- 3D printers — linear carriages, idler pulleys, extruder gears
- Skateboards & longboards — wheel bearings (typically 608ZZ or 608-2RS)
- Fishing reels — spool bearings, level wind, anti-reverse
- Dental and medical equipment — handpieces, autoclavable assemblies (stainless versions)
- Robotics & instrumentation — servos, sensor encoders, gimbal mounts
- Optics — telescope mounts, focusers, panning heads
- Model engineering — live steam, traction engines, ME lathe accessories
Companion ranges
For the broader bearing family, browse our Ball Bearings parent and the Bearings hub. For stainless miniature options (food, dental, marine), see our Stainless Steel Ball Bearings collection. Background reading: Deep Groove Ball Bearing Guide.
Need a specific size?
Call the AIMS team on (02) 9773 0122 or use our contact page. We can source EZO, NSK, NACHI and SKF miniatures through our wholesale partners with 24-48 hour lead time on stock items.