1 Model Information & Technical Parameters

Model：NN 3014 KTN3/SP

Dimensions

Bore d：70 mm

Outer diameter D：110 mm

Width B：30 mm

Bore type: 1:12 tapered bore

Radial clearance: C1 minimal internal clearance

Accuracy class: SP precision grade

Structure: NN double row design, inner ring with three ribs, ribless outer ring allowing axial floating

Outer ring flange: None

Seal: Open design, no seals

Surface coating: Uncoated

Pre-lubrication: No lubricant supplied from factory

Re-lubrication feature: No circumferential lubrication groove and oil holes on outer ring; re-greasing only permitted during machine shutdown

Code Explanation

NN: Double row cylindrical roller bearing, three ribs on inner ring, ribless outer ring with axial floating capacity to compensate spindle thermal elongation, mainly for radial loads with excellent rigidity.

3014: Size series 30 wide cross-section spindle bearing with high load capacity.

K: 1:12 tapered bore, preload adjustable by axial pushing via lock nut.

TN3: Upgraded high-performance non-metallic roller-guided cage, lower friction and improved heat resistance for higher rotational speed.

SP: Precision accuracy grade with strictly controlled rotational runout for precision machine tool spindles.

Load & Speed Data

Basic dynamic load rating Cr：96.8 kN

Basic static load rating C0r：150 kN

Permissible speed, grease lubrication：10 000 r/min

Permissible speed, oil-air lubrication：11 500 r/min

Material & Additional Properties

Rolling element material: Bearing steel

Indicative carbon footprint：3.6 kg CO₂e

Net weight：0.979 kg

eClass code：23-05-09-01

UNSPSC code：31171505

Suffix Explanation

NN: Double row cylindrical roller bearing. Three ribs on inner ring guide two roller rows; ribless outer ring floats axially to absorb thermal expansion, designed primarily for radial loads.

3014: Series 30 wide-section spindle bearing with extended contact length, excellent performance under heavy loads.

K: 1:12 tapered bore. Operators can adjust spindle preload on site by pushing the bearing axially with lock nut.

TN3: Optimized high-performance non-metallic cage. Improved material and geometry deliver lower friction and higher temperature tolerance than standard TN cage for elevated speed operation.

SP: Precision accuracy grade. Tighter tolerances on dimension, radial and axial runout than standard bearings for stable precision during continuous machining.

C1 clearance: Minimal radial internal clearance, suitable for lightly preloaded medium-high speed heavy-duty spindles to suppress vibration and improve workpiece surface quality.

Important reminder: This 1:12 tapered bore NN-type double row cylindrical roller bearing with steel rollers supports on-site preload adjustment. The outer ring has no lubrication groove; continuous re-lubrication during operation is impossible, re-greasing can only be carried out during scheduled shutdown maintenance. NN floating outer ring only bears radial loads and cannot sustain axial force; paired angular contact ball bearings are required for spindle axial positioning. Open bearing without built-in seals; labyrinth seals or oil seals must be installed on housings to block coolant and dust. No pre-filled grease upon delivery. Ideal for intermittent production spindles pursuing high rotating speed without continuous automatic centralized lubrication system.

Alternative variants:

NN3014 KTN/SPW33 (1:12 tapered bore, standard TN cage, W33 groove for non-stop lubrication, 24h continuous production)

NN3014 KTN/SP (1:12 tapered bore, standard TN cage, no lubrication groove, lower maximum speed)

NN3014 KTN3/SPW33 (1:12 tapered bore, TN3 high-speed cage, W33 groove for high speed & continuous lubrication)

NN3014 TN3/SP (straight bore, TN3 cage, no groove, fixed preload)

NN3014 KTN3/UP (1:12 tapered bore, UP ultra-precision grade for mirror surface high-speed grinding spindles)

2 Structure & Operating Characteristics

NN 3014 KTN3/SP is an SP-grade precision double row cylindrical roller bearing with C1 minimal radial clearance, upgraded TN3 high-performance non-metallic cage, bearing steel rolling elements and 1:12 tapered bore without outer ring lubrication channels. Two rows of steel rollers share loads simultaneously to boost radial rigidity and load limit. The NN ribless outer ring slides freely in axial direction to compensate spindle thermal expansion and eliminate extra axial stress caused by temperature rise.

The core advantage lies in adjustable preload via 1:12 tapered bore matched with TN3 high-speed cage. Operators can adjust preload axially using lock nut according to machining requirements. Optimized TN3 cage reduces frictional heat under high-speed operation and achieves superior speed capability compared to conventional TN cage versions. Without W33 groove on outer ring, it cannot connect to on-line continuous lubrication pipelines; lubricant replenishment must be completed during machine downtime. Combined C1 minimal clearance and precision manufacturing tolerances restrain rotary vibration at medium-high speeds and stabilize finishing accuracy.

Selection guide:

NN3014 KTN3/SP (1:12 tapered bore, TN3 high-speed cage, no lubrication groove, SP C1 clearance, intermittent production, high speed demand, re-grease during shutdown, no continuous on-line lubrication)

NN3014 KTN/SP (1:12 tapered bore, standard TN cage, no groove, lower speed limit)

NN3014 KTN3/SPW33 (1:12 tapered bore, TN3 cage, W33 groove, high speed + 24h continuous automatic lubrication)

NN3014 TN3/SP (straight bore, TN3 cage, no groove, fixed preload without field adjustment)

Recommended matching bearing: Paired 7014 SP angular contact ball bearings to bear all axial loads and realize bidirectional spindle axial positioning.

3 Core Performance Advantages

1. Double-row bearing steel roller arrangement delivers powerful radial load capacity and superior spindle rigidity, suitable for high-speed machining with moderate heavy cutting.

2. NN-type wide-section double-row structure achieves uniform load distribution and better anti-tilting performance than single row cylindrical roller bearings.

3. 1:12 tapered bore enables preload adjustment via lock nut, spindle rigidity can be flexibly modified when production process changes.

4. Upgraded TN3 high-performance non-metallic cage reduces friction loss and improves heat resistance, greatly lifting permissible rotational speed.

5. SP precision standard combined with C1 minimal radial clearance ensures tight control over rotational runout, reduces high-speed vibration and stabilizes surface finish.

6. Axially floating outer ring automatically compensates spindle thermal elongation, prevents extra internal bearing stress and extends service life.

4 Typical Application Fields

4.1 Spindles of high-speed precision CNC cylindrical & internal grinding machines

Intermittent production, regular maintenance shutdown, priority for high rotating speed

4.2 Spindle units of medium & small high-speed vertical machining centers

Multi-product processing with frequent parameter adjustment, without 24-hour continuous centralized lubrication system

4.3 High-speed spindles of precision turn-mill composite machines

Batch non-continuous production, lubricant replenishment completed during downtime maintenance

4.4 Precision high-speed rotary spindle equipment

High radial load demand, adjustable spindle preload, no on-line continuous lubrication circuit

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 clean contaminants on shaft journals, housing bores and spacer contact surfaces. For the 1:12 tapered bore, adjust preload by slow and uniform axial pushing with lock nut; violent hammering is forbidden. No oil passage needs to be reserved in housing as outer ring has no lubrication groove. Reliable sealing must be installed on machine housings to block coolant and dust ingress. This NN-type bearing cannot withstand axial loads, paired angular contact bearings are mandatory for spindle axial positioning. Avoid long-term continuous extreme shock loads.

5.2 Selection Guidance

High speed demand, adjustable preload, intermittent production, re-grease only during shutdown, no continuous on-line lubrication → NN3014 KTN3/SP

Adjustable preload, 24-hour continuous operation, equipped with centralized automatic lubrication system → NN3014 KTN3/SPW33

Medium speed, adjustable preload, intermittent production, cost priority → NN3014 KTN/SP

High speed, stable process without preload adjustment, intermittent production → NN3014 TN3/SP

Ultimate rotational accuracy, mirror surface high-speed grinding → NN3014 KTN3/UP

Important notice: Without outer ring lubrication groove, on-line lubricant replenishment during operation is unavailable. Strictly follow maintenance schedule to re-grease periodically. NN double row structure is designed for radial loads only. Sustained axial force leads to edge stress concentration, roller scuffing and premature fatigue spalling.

5.3 Lubrication Maintenance Instruction

No lubricant pre-filled at factory. Oil-air lubrication is recommended to reach maximum permissible rotational speed; premium high-speed grease is suitable for intermittent operation. Due to absence of outer ring W33 oil channels, lubricant cannot be supplemented while machine is running. Set fixed maintenance cycle to clean bearing and refill grease during shutdown. Continuously track bearing temperature; inspect improper preload, grease aging or particle contamination once abnormal temperature rise appears. It achieves better heat control under high speed compared with bearings fitted with standard TN cage, yet continuous operation at top speed requires strict temperature management.

5.4 Environmental Application Notes

Open structure without built-in seals; labyrinth seals or oil seals on bearing housings are compulsory. Rolling contact surfaces are sensitive to hard particles; foreign contaminants easily cause pitting on raceways. TN3 cage is optimized for high-speed conditions, prevent cage contamination by carbonized aged grease. Bearing steel rollers have good load and shock resistance, yet long-term high temperature accelerates lubricant degradation. Arrange regular shutdown maintenance for grease replacement.

6 Fault Identification

Common failure modes: steadily rising vibration during high-speed cutting, regular texture patterns on machined workpieces, abnormal continuous spindle temperature increase, periodic rotational noise, thermal deformation and abrasion of cage, roller scuffing, raceway fatigue spalling. Typical failures for tapered bore bearings: excessive preload leading to persistent overheating; insufficient preload resulting in reduced spindle rigidity and machining chatter marks; grease drying and carbonization caused by overdue maintenance; uneven abrasion of two roller rows induced by unexpected axial loads; dry friction due to lubrication failure under long-term maximum speed operation. Shut down equipment immediately upon persistent abnormal noise or irreversible accuracy degradation. Bearings with permanent damage to raceways, rolling elements or cage cannot be repaired and need complete replacement.