1 Model Information & Technical Parameters

Model：KDN.NAA17XL0M

 

Basic Dimensions (Inch / Metric)

Parameter Inch Metric

Bore diameter (d) 1.750 in 44.450 mm

Outside diameter (D) 2.125 in 53.975 mm

Width (B) 0.1875 in 4.763 mm

Radial cross section (H) 0.1875 in 4.763 mm

Inner ring shoulder diameter (d₁) — ≈48.006 mm

Outer ring shoulder diameter (D₁) — ≈50.419 mm

Ball diameter — 2.381 mm

Fillet radius (r) 0.015 in 0.381 mm

Contact angle 30°

Performance Data

Parameter Value Unit

Dynamic load rating (radial, CK) 1.42 kN

Static load rating (radial, C₀) 2.05 kN

Static load rating (axial, C₀a) 5.07 kN

Dynamic load rating (moment, Cₘ) 0.0262 kN·m

Static load rating (moment, C₀M) 0.0497 kN·m

Operating temperature range -30 ~ +110 °C

Technical Attributes

Supply form: Open thin-section four-point contact ball bearing (with inner and outer rings)

Structure type: KDN.NAA constant-section thin-section four-point contact ball bearing (Type X)

Sealing: Without seal (open)

Cage: Solid brass (machined) cage (suffix M)

Pre-lubrication: None

Material: Bearing steel (AISI 52100 chrome steel)

Load direction: Radial + axial (both directions) + moment (combined loads)

Number of rows: Single row

Tolerance class: ABEC-1

Radial clearance: XL0 precision clearance class

 

Logistics & Industry Codes

Net weight: 0.0227 kg (0.05 lbs)

Indicative carbon footprint: 0.09 kg CO₂e

eClass code: 23-05-08-07

UNSPSC code: 31171538

 

Suffix Explanation

KDN: KAYDON Reali-Slim® thin section bearing series identifier

 

NAA: Radial cross section 3/16 inch (0.1875 in) × Width 3/16 inch (0.1875 in)

 

17: Inner diameter 1.75 inches

 

X: Four-point contact ball bearing (Type X), for combined loads

 

L: Non-metallic cage designation in original design

 

0: XL0 precision clearance class (ABEC-1)

 

M: Solid brass (machined) cage — in KAYDON/SKF nomenclature, suffix M typically indicates a machined brass cage, offering superior strength, temperature resistance and impact resistance compared to non-metallic cages

 

Important reminder: This model is an open thin-section bearing with no seals and no pre-filled grease. Lubricant must be added during installation based on actual operating conditions. Suffix M indicates a solid brass cage, providing superior reliability in high-temperature, high-speed or frequent impact applications. Type X four-point contact design simultaneously accommodates radial, axial and moment loads.

 

2 Structure & Operating Characteristics

Japan NMT KDN.NAA17XL0M is a constant-section thin-section four-point contact ball bearing (Type X) . Its core design principle: the cross-section remains constant as the bore diameter increases. This allows designers to use the same thin-section bearing series across different rotating component sizes, greatly simplifying design and selection while achieving significant space and weight savings.

 

NAA specification indicates a cross-section of 3/16" x 3/16" (0.1875 inch radial section, 0.1875 inch width). At 1.75 inch (44.45 mm) bore, the outside diameter is only 53.975 mm (2.125 inches), achieving exceptional space efficiency.

 

Type X four-point contact design is the core technical feature. Balls contact the raceways at four points, simultaneously accommodating radial loads, bidirectional axial loads, and moment loads. A single bearing replaces the need for paired angular contact ball bearings in face-to-face or back-to-back arrangements, significantly reducing axial space. The 30° contact angle ensures stable operation under various load directions.

 

Solid brass cage (suffix M) is the key differentiator of this model from standard versions. In KAYDON/SKF nomenclature, suffix M typically indicates a machined brass cage. Compared to standard non-metallic (nylon) cages, the solid brass cage offers:

 

Higher strength: Solid brass construction provides greater load capacity for moderate to heavy load conditions

 

Superior temperature resistance: Brass material excels in high-temperature operating environments

 

Enhanced impact resistance: Solid structure withstands frequent shock loads with reduced risk of cage deformation

 

Lower wear: Excellent brass-to-steel friction pairing ensures smoother operation

 

Extended service life: Superior durability under demanding conditions

 

Open construction is an important feature. Without seals or pre-filled grease, the design allows users to flexibly select grease or circulating oil lubrication based on actual operating conditions.

 

XL0 precision clearance class ensures high rotational accuracy and low vibration during operation.

 

Selection reference:

 

KDN.NAA17CL0 (CL0 clearance, Type C radial contact, non-metallic cage, for pure radial loads)

 

KDN.NAA17XL0 (XL0 clearance, Type X four-point contact, non-metallic cage, for combined loads)

 

KDN.NAA17XL0M (XL0 clearance, Type X four-point contact, solid brass cage, for high-temperature/high-speed/impact conditions)

 

3 Core Performance Advantages

1. Type X four-point contact design delivers comprehensive combined load capacity. Simultaneously accommodates radial, axial and moment loads — a single bearing replaces a pair of angular contact ball bearings, significantly saving axial space.

 

2. Constant thin-section design delivers ultimate space and weight savings. Single cross-section remains constant as bore increases — at 1.75" bore, OD is only 2.125" with radial section just 3/16" (4.763 mm). Net weight only 0.0227 kg, ideal for weight-sensitive aerospace and robotics applications.

 

3. Solid brass cage (suffix M) — the reliable choice for demanding conditions. Offers superior strength, temperature resistance and impact resistance compared to non-metallic cages, particularly suitable for high-temperature, high-speed or frequent impact applications.

 

4. Open construction enables flexible lubrication customization. Without seals or pre-filled grease, users can select grease or oil lubrication based on actual conditions, adapting to diverse application requirements.

 

5. XL0 precision clearance ensures smooth and accurate operation. Meets stringent requirements of precision instruments, medical equipment and other high-accuracy applications for low vibration and high rotational precision.

 

6. High precision manufacturing with international standard interchangeability. Made of AISI 52100 bearing steel, ABEC-1 tolerance class, fully interchangeable with KAYDON NAA17XL0M, RBC NAA17XL0-RBC and other equivalent models.

 

4 Typical Application Fields

4.1 Industrial Robotics

Lightweight robot arm joints, automation module rotary supports, precision assembly equipment — Type X design effectively handles moment loads at joints while supporting radial loads. Brass cage is particularly suitable for robots with frequent start-stop cycles.

 

4.2 Aerospace

Satellite mechanisms, lightweight precision components for aircraft, avionics rotary mechanisms — thin and lightweight characteristics make it ideal for aerospace applications, with brass cage providing enhanced reliability.

 

4.3 Medical Equipment

Surgical robots, CT/MRI and other advanced imaging equipment rotating components — low friction and high running accuracy meet the stringent reliability requirements of medical devices.

 

4.4 Precision Instruments & Optical Equipment

Test instrument rotary supports, optical platform fine-tuning mechanisms, precision positioning devices.

 

4.5 High-Temperature, High-Speed or Impact Conditions (M-Type Advantage)

Industrial equipment with sustained high temperatures, high-speed transmission components with frequent start-stop cycles, automation equipment with instantaneous shock loads — the solid brass cage excels in these demanding conditions.

 

5 Assembly Specifications & Usage Guidelines

5.1 Pre-installation Inspection

Verify model and specifications match design requirements. Inspect bearing appearance to ensure no damage or corrosion. Check shaft and housing dimensional tolerances and surface finish against design specifications.

 

5.2 Installation Procedure

Install in a clean environment to prevent dust and contaminants from entering the bearing. Use press-fit method with force applied evenly to the end face of the fitted ring. Never apply force through rolling elements or cage. Although the brass cage offers higher strength, proper handling is still required — avoid direct impact on the cage. Keep bearing level during installation and press slowly to avoid tilting that could score raceways.

 

5.3 Lubrication Maintenance

This model comes without pre-filled grease — lubricant must be added during installation based on operating conditions. High-quality lithium or synthetic grease is recommended. Brass cage has identical lubrication requirements to non-metallic cages. Establish regular oil replenishment schedule; dry running is strictly forbidden.

 

5.4 Environmental Considerations

Operating temperature range: -30°C to +110°C. As this bearing is open construction, additional sealing protection at the equipment level is recommended in high-dust, high-humidity or chemically corrosive environments. Avoid subjecting the bearing to impact loads beyond design limits.

 

6 Fault Identification

Common failure modes: Rolling element or raceway fatigue pitting, abnormal operating noise increase, significant rotation resistance increase, excessive temperature rise, seizure caused by poor lubrication. Brass cage may deform under severe overload. If cage distortion or rolling element damage occurs, replace the entire bearing assembly — repair and reuse are not allowed.