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Clearance - Bearings - Technical
Miniature Bearings and Small Parts

Bearing Clearance

The clearance or radial play of a bearing is equal to the total radial displacement, in the median plane perpendicular to the bearing axis of the inner ring in relation to the outer ring, under the effect of a small measuring force.

clearance Diagram

Exagerated depiction of various levels of Radial Play. The starting amount is also adjusted by other factors such as housing tolerances, loads and temperature.

Because of the complexity of measurement and taking into consideration manufacturing tolerances, radial play is always indicated between two limits. The normal radial play of RMB radial ball bearings is from 6 to 15 Ám (.0002 to .0006"). The normal radial play of our Japanese radial miniature ball bearings is 5 to 15 Ám (.0002 to .0006"). On request, bearings may be supplied with reduced or increased radial play as per the following chart.

Play is not a criterion of the quality of a bearing but if badly chosen or unfavourably influenced during mounting, it can adversely affect the operation and even reduce the working life of a bearing.

Miniature Bearings (Less than 10mm bore size)

This table shows the basic radial clearances available for miniature bearings and applications for these clearances. Dimensions shown in microns Ám 0.001mm and (1/10th’s thou 0.0001").

SPB/ISO Code Description Minimum Maximum Applications
MC1 Tight 0 (0) 5 (2) Radially loaded low backlash gear systems. Very low speed.
MC2 3 (1) 8 (3)
MC3 Standard 5 (2) 10 (4) Tape Guides, Synchros, Servo Motors, Low Speed Electric Motors and Gear Trains. Gyro Gimbals (Horizontal Axis).
MC4 8 (3) 13 (5)
MC5 Loose 13 (5) 20 (8) High speed Electric Motors and Tape Guides. Provides some compensation for axial loading. Gyro Gimbals (Vertical Axis).
MC6 20 (8) 28 (11)

Bearings 10mm bore size and over

This table shows the basic radial clearances available for  bearings over and including 10mm bore size. Dimensions shown in microns Ám 0.001mm.

  Min / Max Clearance
Bore Size Range
SPB/ISO Code Description 10mm Over 10mm to 18mm Over 18mm to 24mm Over 24mm to 30mm Over 30mm to 40mm Over 40mm to 50mm
C2 Tight 0 / 7 0 / 9 0 / 10 1 / 11 1 / 11 1 / 11
CN (standard) Standard 2 / 13 3 / 18 5 / 20 5 / 20 6 / 20 6 / 23
C3 Loose 8 / 23 11 / 25 13 / 28 13 / 28 15 / 33 18 / 36
C4 14 / 29 18 / 33 20 / 36 23 / 41 28 / 46 30 / 51
C5 20 / 37 25 / 45 28 / 48 30 / 53 40 / 64 45 / 73

You can find many types of bearings in the Miniature Bearings and Small Parts Bearings Online Catalogue pages.

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Miniature Bearings and Small Parts offers hundreds of thousands of products in thousands of categories including ball bearings, roller bearings, thrust bearings, ceramic and ceramic hybrid bearings, stainless steel bearings, miniature bearings, linear bearings, shafting, oil seals and adhesives - see the full listing in the Online Catalogue. We have excellent Freight Rates within USA and worldwide. We offer a choice of delivery with a signature required, or cheaper options with no signature required. The no signature required options are at the customer’s risk once the goods leave our store.

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