ISO 9001 Sourced SAE 52100 Chrome Steel

Miniature Ball Bearings

Precision micro-bearings manufactured with ultra-fine tolerances for medical devices, robotics, high-speed spindles, and precision instrumentation.

Miniature Ball Bearings
Standard & Custom Sizes In Stock
Speed Boundary Up to 60,000 RPM
Load Capacity Precision Micro Radial
Protection Open / Shielded (ZZ)
Fit & Clearance P5 / P4 (ABEC-5/7)
Engineering Data Sheet

Technical Specifications & Sizing Chart

Standard metric dimensional chart and load parameters. Filter by model, bore (d), outer diameter (D), or width (B).

Technical Specifications & Sizing

Bearing No. outer diameter (mm) outer diameter (inch) inner diameter (mm) inner diameter (inch) thinkness (mm) thinkness (inch) Load Rating Cr (N) Load Rating Cor (N) Max Speed Oil (r/min) Reference Weight (kg)
603 3 0.118 10 0.394 4 0.157 553 203 49500 0.14
604 4 0.157 12 0.472 4 0.157 1170 476 40500 0.148
605 5 0.197 14 0.551 5 0.197 1947 757 45400 0.27
606 6 0.236 17 0.669 6 0.236 2358 954 38000 0.4
607 7 0.276 19 0.748 6 0.236 2358 954 36000 0.5
608 8 0.315 22 0.866 7 0.276 2970 1224 34200 0.6
609 9 0.354 24 0.945 7 0.276 3015 1269 30600 0.75
623 3 0.118 10 0.394 4 0.157 553 203 45000 0.14
624 4 0.157 13 0.512 5 0.197 1170 476 38700 0.2
625 5 0.197 16 0.63 5 0.197 1566 603 32400 0.3
626 6 0.236 19 0.748 6 0.236 2358 954 34200 0.4
627 7 0.276 22 0.866 7 0.276 2970 1224 32400 0.5
629 9 0.354 26 1.024 8 0.315 4095 1773 28800 0.75
633 3 0.118 7 0.276 2 0.079 283 103 61200 0.06
634 4 0.157 16 0.63 5 0.197 576 203 59400 0.78
635 5 0.197 19 0.748 6 0.236 954 342 59400 0.82
636 6 0.236 22 0.866 7 0.276 2970 1224 30600 1.03
637 7 0.276 26 1.024 9 0.354 3660 1422 27000 1.24
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Micro-Engineered for Extreme Precision

Miniature Ball Bearings are small bearings with deep groove raceways designed for high rotational accuracy and minimal frictional torque in space-constrained applications.

BMT Impex offers miniature bearings with bore sizes as small as 1mm, available in stainless steel (AISI 440C) or chrome steel with synthetic lubrication options.

Miniature Ball Bearings Category
Engineering Insights

Bearing Nomenclature & Clearance Guide

Understanding technical suffixes, clearance prefixes, and material ratings used in industrial procurement.

Suffix & Prefix Reference

  • 2RS / DDU: Double lip synthetic NBR rubber seals for moisture & dust exclusion.
  • ZZ / 2Z: Double pressed-steel non-contact shields for grease retention at high speeds.
  • K / N: Tapered bore (K) or snap ring groove (N) for specific mounting configurations.
  • M / Y: Machined brass cage (M) or pressed steel cage (Y) for heavy industrial loads.

Radial Internal Clearance (RIC)

  • C2 (Tight): Less than normal clearance. Used for high-precision shafts to minimize vibration.
  • CN (Normal): Standard fit for general industrial applications under normal temperatures.
  • C3 (Loose): Greater than normal clearance. Compensates for thermal expansion in electric motors.
  • C4 / C5: Massive internal space for kilns and gearboxes running at extreme temperatures.
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