1 Model Information & Technical Parameters

Model：N 1011 KTNHA/SP

Dimensions

Bore d：55 mm

Outer diameter D：90 mm

Width B：18 mm

Bore type: 1:12 tapered bore

Radial clearance: C1 minimal internal clearance

Accuracy class: SP precision grade

Structure: Inner ring with two ribs, ribless outer ring, separable inner and outer rings

Outer ring flange: None

Seal: Open design, no seals

Surface coating: Uncoated

Pre-lubrication: No lubricant supplied from factory

Code Explanation

N: Single row cylindrical roller bearing, inner ring double ribs, ribless outer ring, outer ring allowed axial displacement

1011: Size series 10, light cross-section optimized for high speed operation

K: 1:12 tapered bore. Axial tension expands inner ring radially for adjustable preload during assembly

TNHA: High-temperature modified polyamide solid non-metallic roller-guided cage, higher thermal resistance than standard TN cage

SP: Precision accuracy grade with tight dimensional tolerance and rotational runout for precision spindles

Load & Speed Data

Basic dynamic load rating Cr：39.1 kN

Basic static load rating C0r：46.5 kN

Permissible speed, grease lubrication：17 000 r/min

Permissible speed, oil-air lubrication：24 000 r/min

Material & Additional Properties

Material: Bearing steel

Re-lubrication: External re-lubrication applicable

Indicative carbon footprint：1.4 kg CO₂e

Net weight：0.38 kg

eClass code：23-05-09-01

UNSPSC code：31171505

Suffix Explanation

N: Single row cylindrical roller bearing with double-ribbed inner ring and ribless outer ring. The outer ring can float axially to compensate thermal elongation of shaft and avoid extra axial stress caused by temperature rise.

1011: Lightweight Series 10 with narrow cross-section, low friction loss, designed primarily for high-speed spindle applications.

K: 1:12 tapered bore. Preload can be precisely set by lock nut expansion to improve radial rigidity of spindle.

TNHA: Heat-resistant modified polyamide cage. Low friction non-metallic construction, suitable for long-term continuous high-speed operation.

SP: Precision accuracy grade. Superior geometric accuracy and controlled radial/axial runout compared to normal tolerance class.

C1 clearance: Minimal radial internal clearance, dedicated for preloaded precision spindles to suppress vibration under high rotating speed.

Important reminder: The outer ring can move axially; this bearing cannot carry axial loads independently. It must be combined with angular contact ball bearings to withstand axial force. C1 minimal clearance is sensitive to fit and operating temperature. Excessive preload leads to sharp temperature rise and cage damage. No integrated seals; labyrinth seals or oil seals are required to block coolant and dust. Even TNHA high-temperature cage has temperature limits; avoid continuous over-temperature operation. Never hammer bearing during assembly; hydraulic nut is recommended for uniform preload application.

Alternative variants:

N1011 KTNHA (standard precision, 1:12 tapered bore high temp cage)

N1011 KTNHA/SP (SP precision grade + C1 clearance, preferred for high-speed precision spindles)

N1011 KTN/SP (standard TN cage, SP precision class)

N1011 KTNHA/UP (UP ultra-precision grade for ultra-high precision machinery)

2 Structure & Operating Characteristics

N 1011 KTNHA/SP is a lightweight single row high-speed cylindrical roller bearing, SP precision grade with C1 minimal radial clearance, equipped with TNHA high-temperature polyamide cage. Series 10 narrow cross-section reduces self-weight and rolling friction to deliver excellent high-speed performance. The 1:12 tapered bore enables adjustable preload to boost radial rigidity during assembly. The ribless outer ring allows free axial floating, absorbing thermal elongation of spindle and eliminating induced axial stress inside bearing.

This bearing has no oil groove on outer ring and suits external centralized oil-air or circulating oil lubrication. No grease pre-filled, continuous external lubrication system is required. C1 minimal clearance is engineered for preloaded high-speed spindles to reduce high-speed vibration.

Selection guide:

N1011 KTNHA/SP (taper bore high temp cage, SP precision, C1 clearance, high-speed precision spindles)

N1011 KTNHA (standard precision for general high-speed rotary equipment)

N1011 KTN/SP (standard TN cage for precision machines with moderate ambient temperature)

N1011 KTNHA/UP (ultra-precision machining under extreme rotational speed)

Recommended matching bearing: 7011 SP grade precision angular contact ball bearing to form complete spindle support and undertake axial loads.

3 Core Performance Advantages

1. Light Series 10 cross-section creates low friction loss, maximum speed up to 24000 r/min under oil-air lubrication, satisfying various high-speed spindle demands.

2. TNHA modified high-temperature non-metallic cage offers better heat resistance than ordinary nylon cage, fit for long-hour non-stop high-speed production.

3. 1:12 tapered bore allows flexible on-site preload adjustment, balancing low heat generation at high speed and radial rigidity during cutting.

4. SP precision standard combined with C1 minimal radial clearance strictly controls rotational runout, suppresses high-speed vibration and guarantees machining accuracy.

5. Axially floatable outer ring automatically compensates spindle thermal elongation, prevents extra internal stress from temperature change and extends service life.

6. Manufactured from high-quality bearing steel with stable contact performance between raceways and rollers, sufficient load capacity to balance high speed and load carrying.

4 Typical Application Fields

4.1 High-speed precision CNC lathe spindles

Finishing spindles of medium & small high-speed CNC lathes and sliding head machines requiring high rotational speed, stable precision and oil-air lubrication

4.2 High-precision internal & cylindrical, tool grinder spindles

Spindle units for precision grinding equipment operating continuously at high speed with strict requirements on temperature rise and vibration

4.3 High-speed machining center and engraving-milling machine spindles

Light cutting & finishing applications with obvious shaft thermal elongation requiring floating radial support bearings

4.4 Other high-end high-speed precision rotary mechanisms

High-speed rotary components needing adjustable preload, thermal elongation compensation and precise radial positioning

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

SP precision bearings should be assembled in constant-temperature dust-free clean workshops. Thoroughly remove contaminants from shafts, housings and spacers. Strictly control fit tolerances of shaft journals and housing bores. Apply uniform preload to tapered bore inner ring via hydraulic nut; hammering bearing faces is prohibited. C1 minimal clearance is highly sensitive to preload; preload travel must follow spindle design data to avoid over-preloading. After assembly, perform gradual speed-up and no-load running-in test to monitor temperature and vibration. Install reliable sealing structure to prevent dust and coolant intrusion into rolling zone.

5.2 Selection Guidance

High-speed finishing, obvious shaft thermal elongation, oil-air lubrication, high precision demand → N1011 KTNHA/SP

High-speed operation, moderate temperature, cost control, medium precision requirement → N1011 KTNHA

Long continuous high-speed operation, high ambient temperature → choose TNHA cage version

Ultra-precision mirror machining, extreme rotational accuracy target → N1011 KTNHA/UP

Important notice: Outer ring floating design cannot support axial loads; must be combined with precision angular contact ball bearings.

5.3 Lubrication Maintenance Instruction

No lubricant pre-filled at factory. Oil-air lubrication is preferred for top speed; high-speed grease with periodic re-greasing is acceptable for medium-low speed. Continuously monitor bearing temperature and avoid sustained over-temperature operation. Regularly inspect sealing performance to stop pollutant ingress. Interruption of lubrication will trigger premature wear of cage and rollers.

5.4 Environmental Application Notes

Open construction without built-in seals; labyrinth seals or contact oil seals are mandatory. Rolling surfaces are sensitive to hard particles; tiny contaminants cause rising vibration and rapid accuracy degradation. Avoid continuous shock loads which create indentations on raceways and rollers. Make full use of outer ring floating characteristic to release thermal stress; do not restrict axial movement of outer ring forcibly.

6 Fault Identification

Common failure modes: increased vibration at high speed, poor surface texture of machined workpieces, abnormal spindle temperature rise, periodic rotation noise, cage abrasion, roller edge scuffing and raceway fatigue spalling. Stop machine immediately once continuous abnormal noise or irreversible accuracy loss occurs. Bearings with permanent damage on raceways, rollers or cages cannot be repaired and require full replacement.