GMN uses exclusively high-quality materials for all components and machining processes for manufacturing high-precision spindle and deep groove ball bearings. The highest quality ensures the best-possible performance efficiency and longest life expectancy for GMN products. GMN’s on-going development processes ensure that GMN’s ball bearings are constantly improved, and their technical characteristics continue to evolve.

Inner and outer rings

GMN ball bearings internal and external rings are made of high-quality bearing steal (chrome steel), 100 Cr 6.
Designs in special steels upon request

  • Material
    Rolling bearing steel (chrome steel) 100 Cr 6 Material no. 1.3505, SAE 52100, SUJ2
  • Permissible operating temperature
    Heat stabilized up to a continuous operating temperature of 150 °C (short-term up to 180 °C)
  • Hardness
    60 to 64 HRC, through-hardened; Corresponds to 700-800 HV30 characteristics
    High purity and homogeneity, vacuum degassed
Inner ring 
Outer ring 

Outer ring diameter coating on the Bearings- Outer ring with SliCoTec

GMN customers have come to appreciate the benefits of a DLC-coated outer ring surface over many years of experience. It provides significant added value when used in a floating bearing.

Benefits and characteristics::
  • Significantly reduced sliding friction in loose bearings
  • Prevents corrosion
  • Outer diameter still within DIN tolerances
  • Optimized thin-film technology ensures consistent high precision
  • The DLC layer adheres firmly to the bearing ring
  • Saving additional sliding elements (such as ball bushings)
  • Longer service interval times due to less wear in the bearing seat

Delivery notes

All standard bearings are available as follows:

  • Designs S, SM, KH, series 60.., 62.., 618.., 619..
  • Contact angle C, E or customer-specific
  • Accuracies P4 and ABEC 7, HG, UP
  • Steel or ceramic balls
  • Sealed, with grease-life lubrication – open, for oil lubrication
  • Special bearing coatings on request

The technical information sheet “SliCoTec outer ring coating” can be found here or in other technical information sheets in our area.


The TA and TXM cage designs ensure extraordinary results in regards to RPM, load capacity and life expectancy due to their outstanding characteristics.

TA Cage (Hard mesh)

  • Material: Hard mesh (phenol resin with fine-mesh cotton mesh)
  • Permissible operating temperature:  120°C
  • Cage guidiance: on the outer ring
  • Fabrication: Machined
  • Application: for types S, SM, KH, universal use
  • Characteristics: low friction coefficient, for grease and oil lubrication


  • Material: High-performance, partially crystalline high-performance plastic, PEEK (polyetherether ketone), carbon-fiber reinforced
  • Operating temperature: 250°C
  • Cage guidiance: on the outer ring, ball-bearing
  • Fabrication: injected
  • Application: for types S, SM, optimized for grease lubrication
  • Characteristics: low coefficient of friction, reduces and eliminates cage vibrations, high mechanical, chemical and thermal stability

Advantages of TXM cages

  • High wear resistance
  • Excellent emergency running properties due to favorable sliding properties and reduced abrasion
  • Reduced operating temperature due to lower friction and more favorable tribology
  • Constant grease lubrication due to grease reservoirs in the provided cage pockets
  • Long lifespan
  • Increase the efficiency of the application

Other cage materials, shapes, special treatments (such as TB, brass, Torlon, Al-bronze silver plated) are available upon request.

You can find the “TXM Cage” technical information sheet here or in our download area.



GMN high-precision deep groove ball bearings are basically equipped with a steel cage (J cage). Depending upon demands (such as high RPM), further cage designs of various materials are available.

J Cage (Sheet steel)

  • Material: Sheet steel
  • Operating temperature: 220 °C
  • Fabrication: two-piece, lobed or riveted

T9H Cage (Polyamide)

  • Material: Polyamide (glass fiber reinforced)
  • Operating temperature: 140 °C
  • Fabrication: one-piece, crown cage

TBH Cage (Hard mesh)

  • Material: Hard mesh
  • Operating temperature: 120 °C
  • Fabrication: one-piece, crown cage

TA, TB Cage (Hard mesh)

  • Material: Hard mesh
  • Operating temperature: 120 °C
  • Fabrication: two-piece, riveted


Whether made of chrome steel or ceramic (hybrid ball bearings), ball bearings from GMN fulfill the highest quality demands and ensure the best-possible performance efficiency and life expectancy.

Standard Material (Chrome Steel)

  • Material
    Roller bearing steel (chrome steel) 100 Cr 6 Material no. 1.3505, SAE 52100, SUJ2
    Special steels on request
  • Permissible operating temperature
    Heat stabilized up to a continuous operating temperature of 150° C (short-term up to 180° C)
  • Hardness
    60 to 64 HRC, through-hardened; Corresponds to 700-800 HV30 characteristics
    High purity and homogeneity, vacuum degassed ball bearing with steel balls
ball bearing with steel balls 

Special Material (Ceramics)

The material characteristics of ceramic balls in hybrid bearings result in significant increases in machine performance (in comparison to ball bearings using steel balls), especially under critical conditions.

  • Material
    Ceramic (silicon nitride Si3N4)
  • Material properties
    Low affinity to 100 Cr 6
    Low coefficient of friction
    Low thermal conductivity
    Corrosion resistance
    No magnetism
    Electrically insulating
    Hybrid ball bearing


hybrid bearing 


Ball bearings with a material combination of bearing steel (inner and outer rings) and ceramic (balls) are called ‘hybrid’ ball bearings. All ball bearings can be supplied as hybrid ball bearings.

Advantages of Hybrid Ball Bearings

Long Life

Due to their characteristic material properties, hybrid ball bearings last more than twice as long as steel bearings. Machine run times are significantly increased.

High RPM’s

Due to their tribological properties and lower mass forces – compared to bearings with steel balls – speed increases of up to 30 % can be achieved with hybrid ball bearings.

Lower-Cost Lubrication

The maximum RPM for grease and oil lubrication is increased. Thus hybrid ball bearings can frequently use grease lubrication instead of more expensive oil lubrication.

Higher Processing Efficiency

The higher bearing rigidity, reduced thermal expansion and lower vibration excitation of hybrid ball bearings ensure maximum machining accuracy.

Greater Stiffness

General radial and axial stiffness increases due to the material characteristics of hybrid ball bearings. The benefits are increased precision and displacement at critical own frequencies.

Application examples for Hybrid Ball Bearings

  • Machine tool spindles
  • Fast running machine bearings
  • Durability-optimized precision bearings



Bore/roll ratio





Properties of ceramic (silicon nitride) Si3N4 and rolling bearing steel (chrome steel) 100 Cr 6