Miniature Precision Thrust Bearing Selection Checklist

by Kevin Sweeney
15 December, 2023
9 min read

Miniature Thrust bearings consist of a bearing washer with or without a raceway groove and a retainer incorporating a ball. They are designed for axial loads in only one direction. The friction torque is small and is generally applied in low to medium rotational speed applications. Thrust ball bearings are designed to take axial (thrust) loads at high speeds, but cannot tolerate radial loads. 

Companies like ISC and NSK have the technical capabilities to manufacture reliable submicron precision bearings. Companies like NSK and ISC have the development abilities to meet customer needs and the engineering prowess to innovate. Companies like NSK Micro Precision  and ISC manufacture ball bearings and are the leaders in miniature bearing manufacturing technology. Pacific International Bearings is a leading USA based Distribution company and specializes in high precision miniature ball bearings. PIB has stock on most sizes of NSK/ISC thrust ball bearings in Union City California USA. 

Buy miniature thrust ball bearings by visiting the online store at Pacific International Bearing Sales Inc.

In  precision instrumentation applications such as medical devices, and mini actuators, choosing the appropriate miniature thrust bearings is critical. This article offers engineering-focused criteria for selection, covering material types, axial load capacities, and dimensional tolerances.

Miniature thrust bearings 
Fig1. Miniature thrust bearings 

Miniature Thrust bearings consist of a flat bearing washer without a raceway groove and a retainer incorporating a ball. It can load only axial loads in one direction. The friction torque is small. Applicable for low-speed rotation.

Miniature thrust ball bearing with grooved races
Fig. 2 Miniature thrust ball bearing with grooved races

Thrust ball grooved races

When the races are grooved a higher rated load is achieved. When a raceway groove is added it reduces the contact between the shaft and the housing by capturing the movement of the ball and retainer during rotation.

Miniature Thrust ball bearings are intended for applications with high axial loading, lower speeds and a relatively high torque. Some companies like Timken precision offer these bearings standard in stainless steel to be used where inert materials are required. Typical applications include fuel control systems.

Other Applications for Miniature Thrust ball bearings include medical devices, surgical devices, all types of medical instruments, office automation equipment, small tools, power tools, electric motors, small gearboxes, gear reducers, science and laboratory equipment, automotive and numerous industrial and commercial applications. There is no limit for applying small miniature thrust ball bearings to take advantage of the small envelope design potential.

Miniature Thrust Angular Contact Ball Bearings
Fig.3 Miniature Thrust Angular Contact Ball Bearings

NSK, ISC  Angular contact bearing for JIS 69 series allows for the downsizing of the ball screw support unit. NSK, ISC miniature thrust angular contact bearings will have three times higher axial stiffness than standard deep groove ball bearings. 

ISC /NSK offer a comprehensive line of maintenance free high quality double shielded, lubed for life micro bearings. After purchase ISC/NSK provide easy installation instructions with preloads and recommended torque tightening values with every bearing.

ISC/NSK miniature thrust bearings are available with anti-fretting grease (EA7) and clean grease (LG2)

These bearings are available with P5 class accuracy.

Applications for Miniature Thrust Angular Contact ball bearings include ball screws, actuators, robotic arms, gear reducers to name a few. Companies like NSK/ISC offer Standard specification (material + grease) high carbon chromium bearing steel SUJ 2 + Long Life Urea Grease EA7.

Stainless steel ES-1 + Low particle emission grease LG2.

Part NumberIDODWidth (MM)
MTA 02-06263
MTA 03-08384
MTA 04-114114.5
MTA 05-135135
MTA 06-156155.5
MTA 08-198196.5
Part numbers for this series are shown as single bearings with dimensions

These bearings as universally ground can be paired in (DB) back to back, tandem (TD), or (DF) face to face configurations.

DB type (bronze color matched)
Fig. 4.

DB type (silver color matched)
Fig 5. 

Compact support unit for ball screw support

The industry’s first lightweight, compact and higher stiffness support unit for supporting miniature ball screws of 3 to 8 mm is now available.

Compact Bearings
Fig 6.

To purchase compact support units for ball screw supports contact [email protected]

Pivot Ball Bearings

ISC Pivot ball bearings consist of an outer ring and several balls and supports a conical section (usually 60 degree pivots) at the tip of the rotating shaft. Friction torque is small due to the small pitch diameter of the ball and the shape of the pivot part of the shaft.

Pivot ball bearings
Fig.7 ISC Pivot ball bearings

ISC Pivot ball bearing part numbers begin with the 3mm (D) size and increase with the BCF4X(4mm) BCF5(5mm), BCF6(6mm), BCF7(7mm), BCF8(8mm), BCF9(9mm), BCF10(10mm), BCF12 (12mm), BCF12X(12mm), BCF13(13mm), BCF14(14mm), BCF16(16mm).

Pivot ball bearings range in size from 0.0600 into 0.3750 in in addition to the metric dimensions above.  They are designed for tight space applications where low torque is a requirement. Pivot bearings use the mating shaft as the inner raceway. This bearing type achieves maximum power density with a full complement of large sized balls. They are designed with no cage separator or inner ring. Some manufacturers offer this type of bearing with shields. A typical application is for guidance systems or in commercial gyroscopes.

Load-Bearing Capacity

A fundamental criterion in the selection of miniature thrust bearings is their ability to handle axial loads. This capability is quantified by load ratings provided by manufacturers, but it’s also crucial to understand how to calculate these values based on specific application requirements.


Choosing the right miniature thrust bearing requires evaluation of speeds and loads and bearing materials. The bearing engineer must consider the  load-bearing carrying capacity, dimensional tolerances, and lubrication requirements. Material selection can vary from  440C stainless steel to AISI 52100 steel and can include the use of  Silicon Nitride ceramic balls, and flat or grooved washers. Axial load capacity, calculated through engineering formulas, is important in selecting the correct bearing for your application.

For your specific bearing requirements, including the procurement of high-quality miniature thrust bearings, consider PIB Sales as your reliable distributor. Contact us to get help.

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Written by

Kevin Sweeney

Founder and CEO at Pacific International Bearing Sales Inc (PIB)
Education: BS Business and Economics California State University Hayward Ca
CBS (Certified Bearing Specialist)

My role with Pacific International Bearings (PIB) is currently CEO. Since 1976, I have been deeply involved in the bearing industry, working in manufacturing sales at NTN Bearing and subsequently in Bearing Distribution. Before establishing PIB in 1990, I gathered valuable experience in bearing manufacturing and distribution. The last 45 + years in the bearing industry have been both rewarding and challenging, assisting customers across a large number of diverse bearing applications.
Outside of the bearing industry, my interests are family, woodworking, motorcycling, cars, gardening, and golf.
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