1 Model Information & Technical Parameters

Model：NN 3015 KTN/SPW33

Dimensions

Bore d：75 mm

Outer diameter D：115 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: Outer ring equipped with W33 circumferential lubrication groove and oil holes, continuous re-lubrication available during operation

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.

3015: 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.

TN: Standard non-metallic roller-guided cage, stable performance for long-term continuous operation.

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

W33: Outer ring fitted with circumferential lubrication groove and oil holes for on-line continuous lubricant supply.

Load & Speed Data

Basic dynamic load rating Cr：96.8 kN

Basic static load rating C0r：150 kN

Permissible speed, grease lubrication：7 500 r/min

Permissible speed, oil-air lubrication：8 500 r/min

Material & Additional Properties

Rolling element material: Bearing steel

Indicative carbon footprint：3.9 kg CO₂e

Net weight：1.05 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.

3015: 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.

TN: Standard non-metallic roller-guided cage with mature and stable structure, suitable for non-stop mass production.

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.

W33: Circumferential lubrication groove and oil through holes machined on outer ring. Oil channels can be processed in bearing housing to deliver lubricant while machine is running.

Important reminder: This 1:12 tapered bore NN-type double row cylindrical roller bearing supports on-site preload adjustment. The outer ring is equipped with W33 lubrication groove and oil holes, compatible with centralized lubrication system for non-stop re-greasing under 24/7 production. 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 precision spindle equipment with continuous mass production and automatic centralized lubrication circuit.

Alternative variants:

NN3015 KTN/SP (1:12 tapered bore, standard TN cage, no W33 groove, re-lubricate only during shutdown, intermittent production)

NN3015 KTN3/SPW33 (1:12 tapered bore, TN3 high-speed cage, W33 groove, higher limiting rotational speed)

NN3015 TN/SPW33 (straight bore, TN cage, W33 groove, fixed preload without field adjustment)

NN3015 KTN/UPW33 (1:12 tapered bore, UP ultra-precision grade for ultra-high precision continuous grinding spindles)

2 Structure & Operating Characteristics

NN 3015 KTN/SPW33 is an SP-grade precision double row cylindrical roller bearing with C1 minimal radial clearance, standard TN non-metallic cage, bearing steel rolling elements and 1:12 tapered bore. The outer ring is machined with W33 circumferential lubrication groove and oil holes. 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 advantages are adjustable preload via 1:12 tapered bore matched with W33 outer ring lubrication structure. Operators can adjust preload axially using lock nut according to machining requirements. The W33 lubrication design can connect to centralized lubrication system to supply lubricant continuously during non-stop production, meeting all-day manufacturing demands. Mature standard TN cage delivers outstanding reliability for long-duration stable operation. Combined C1 minimal clearance and precision manufacturing tolerances restrain rotary vibration at medium-high speeds and stabilize finishing accuracy.

Selection guide:

NN3015 KTN/SPW33 (1:12 tapered bore, TN cage, W33 lubrication groove, SP C1 clearance, 24h continuous production, centralized automatic lubrication, adjustable preload)

NN3015 KTN/SP (1:12 tapered bore, TN cage, no lubrication groove, intermittent production, re-grease only at shutdown)

NN3015 KTN3/SPW33 (1:12 tapered bore, TN3 high-speed cage, W33 groove, continuous spindles requiring higher limiting speed)

NN3015 TN/SPW33 (straight bore, TN cage, W33 groove, fixed preload without on-site adjustment)

Recommended matching bearing: Paired 7015 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 medium-speed continuous 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. Mature TN non-metallic cage ensures stable and reliable operation, perfectly adapted to long-term non-stop mass production.

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

6. W33 lubrication groove and oil holes on outer ring allow connection with centralized lubrication system to supply lubricant continuously during operation, ideal for all-day mass production.

7. 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 continuously operated CNC cylindrical & internal grinding machines

24-hour batch production with centralized lubrication system, minimizing maintenance shutdowns

4.2 Spindle units of medium & large vertical and horizontal machining centers

Long-term non-stop operation, priority for long-duration spindle stability

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

Continuous machining of bulk components equipped with automatic oil-air/grease centralized lubrication circuit

4.4 Precision high-speed rotary spindle equipment on automated production lines

High radial load demand, adjustable spindle preload, requiring continuous on-line lubricant supply

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. Corresponding oil passages should be machined in bearing housing to align with outer ring W33 lubrication holes for smooth oil supply. 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

24-hour continuous mass production, adjustable preload, equipped with centralized automatic lubrication system → NN3015 KTN/SPW33

Adjustable preload, intermittent production, no on-line oil supply, re-grease only during shutdown → NN3015 KTN/SP

Continuous production, adjustable preload, higher limiting speed required → NN3015 KTN3/SPW33

Continuous production, stable process without preload adjustment → NN3015 TN/SPW33

Ultimate rotational accuracy, mirror surface continuous grinding → NN3015 KTN/UPW33

Important notice: When supplying lubricant via W33 channel, control lubricant flow properly to avoid excessive oil supply leading to temperature rise. 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 system is recommended for long continuous operation; premium long-life high-speed grease applies to batch production grease lubrication conditions. Continuous lubricant supply during operation is available through outer ring W33 groove, yet grease aging and particle contamination need regular inspection. Continuously track bearing temperature; inspect improper preload, lubricant flow rate or particle contamination once abnormal temperature rise appears. Compared with TN3 upgraded cage version, its limiting speed is lower, but outstanding stability for long continuous operation.

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. TN cage fits regular continuous medium-speed working conditions; extreme high temperature that accelerates cage aging should be avoided. Bearing steel rollers have good load and shock resistance. Continuous lubrication effectively slows down lubricant degradation and reduces wear rate under long continuous operation.

6 Fault Identification

Common failure modes: steadily rising vibration during 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; insufficient lubricant flow from centralized system causing lubrication failure; uneven abrasion of two roller rows induced by unexpected axial loads; blockage of W33 oil passages resulting in local oil starvation and dry friction. 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.