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Factory-Direct Distributor for EZO Bearings & Sapporo Bearings

EZO Bearings are distirbuted by AST BearingsAST Bearings (USA) is proud to be the only authorized, national stocking distributor in North America for EZO Bearings & Sapporo Bearings - a world recognized manufacturer of high-precision miniature ball bearings from Japan and China.  As an authorized EZO bearings distributor, AST® Bearings stocks their products receiving them directly from the factory.  Feel free to contact us directly about any EZO bearing product.

Sapporo Precision Group has been fostering the "EZO Bearings" brand for many years now. EZO Bearings has achieved remarkable growth from a number of domestic and foreign users in 28 different countries throughout the world. In 2003, the Sapporo Precision Group decided to introduce a new brand "SPB" subsequent to "EZO Bearings". "SPB" is the combination of two names, Sapporo Precision Bearings and Shanghai Precision Bearings, which implies the pride of their Super Precision Bearings.

EZO Bearing Factories - Two locations, both exceptional

Sapporo Precision Bearings has set-up the most advanced bearing manufacturing plants in Ashibetsu, Hokkaido, Japan and in Shanghai, China. Furthermore, the products produced in Sapporo Precision Bearings' Precision plant in China are from the same exceptional quality Japanese steel and Japanese machinery used in the manufacturing process is the High Precision grade from Japan. This allows both  Japanese and Chinese factories to consistently supply highest quality, high-precision ball bearings to the world market.

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EZO Bearing Catalogs

EZO Product Catalog Cover - Product Dimension SectionEZO Product Catalog Cover - Technical SectionEZO's printed bearing catalogs covers only a sampling of the over 5,000 products they can manufacture.  Bearings covered in the EZO catalogs include:

  • Metric Series
  • Inch Series
  • Extra Thin Metric Series: 6700, 6800, and 6900
  • Large Sized Stainless Series: 6000H, 6200H, and 6300H
  • Extra Thin Metric Series: ET and ER
  • Thrust Series: FM and F

To download a copy of the EZO Bearing Catalogs, please visit here.

Sapporo Precision Bearings Product Line

There are over 800 "basic" EZO bearings with over 5,000 different kinds available (not including countless custom-made bearings). Sapporo Precision Bearings specialize in manufacturing High Precision Ball Bearings such as Miniature Precision Ball Bearings, Extra Thin Type bearings, Flanged Bearings and Stainless Bearings with sizes ranging from a mere 0.6 mm Bore diameter to 90 mm and O.D sizes from 2.5 mm to 100 mm. Sapporo Precision Bearings' standard material for rings and balls is a vacuum degassed high carbon chromium steel allowing for high efficiency, low torque, low noise level and long bearing life. For bearings requiring anti-corrosion or heat-resistance properties, KS440 martensitic stainless steel is used (see below for more information).

EZO Extra-Miniature Bearings

  • Extra-miniature bearings are suitable for products requiring high-speed rotation, low-friction torque, low vibration and low noise.

EZO Extra-Thin Type Bearings

  • Thin bearings facilitate design downsizing and weight saving. A wide variety of thin bearings is available.

EZO Large-Sized Stainless Steel Bearings

EZO Extra-Thin Type Flanged Bearings

  • Extra- thin type flanged bearings are used for the downsizing and lightweight designing because of their thin cross section.

EZO Steel Balls

  • The steel balls used in Sapporo Precision Bearings' precision products, conform ball bearing rolling element quality with minimum deviation of sphericity and surface roughness. The sizes range from a diameter of 0.3mm to 114.3mm and are available in either high carbon chromium steel, which offers high wear resistance and load carrying capacity or in stainless steel that offers corrosion and wear resistance.

EZO Standard Classes

  • Standard-class products are manufactured at one class better than standard quality in dimensional accuracy.

EZO Precision Classes

  • This type of bearing with high precision is suitable for products requiring low-torque, low vibration and high-speed rotation.

Miniature bearings are vital parts used in cars and trucks, computer peripheral equipment, audio and video devices and many other applications used in everyday life. With AST Bearings and Sapporo Precision Bearings working together you are assured of getting not only a the highest quality products in miniature ball bearings by Sapporo Precision Bearings, but a solution to precision applications and complete support from added-value services offered by AST Bearings.

EZO Bearing Materials

The standard material for EZO rings and balls is a vacuum degassed high-carbon chromium steel. This allows for bearings with high efficiency, low torque, low noise level, and long bearing life.

However, for bearings requiring corrosion or heat-resistant properties, EZO uses the improved martensitic KS440 stainless steel (also known as ACD34) for all of its stainless steel bearings (not 440C as some bearing factories still do).

Chemical Composition of Select Bearing Steels

SUS440C KS440
0.95~1.10 0.95~1.20
Si 0.15~0.35 ≤1.00 1.00
Mn 0.50 1.00 1.00
P 0.025 0.040 0.030
S 0.025 0.030 0.020
Cr 1.30~1.60 16.00~18.00 11.50~13.00
Mo 0.08 ≤0.75 0.30
EQUIVALENT SAE52100 & 100Cr6 AISI440C &

How to Purchase EZO Bearing Products

Contact us directly if you have a need for any EZO bearing products. AST is the USA's only authorized, national stocking, factory-direct distributor for EZO products and will provide you with "value beyond the part."

Request a Quote for EZO Bearings


EZO® and SPB® are registered trademarks of Sapporo Precision, Inc. of Sapporo, Hokkaido, Japan

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