1 Model Information & Technical Parameters

Model：NN 3014 KTN/SPW33

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

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.

TN: Non-metallic roller-guided cage, low friction and controlled temperature rise.

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

W33: Outer ring equipped with circumferential lubrication groove and oil holes for continuous lubricant replenishment.

Load & Speed Data

Basic dynamic load rating Cr：96.8 kN

Basic static load rating C0r：150 kN

Permissible speed, grease lubrication：8 000 r/min

Permissible speed, oil-air lubrication：9 000 r/min

Material & Additional Properties

Rolling element material: Bearing steel

Indicative carbon footprint：3.6 kg CO₂e

Net weight：0.983 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.

TN: Non-metallic cage, lightweight, reduces friction and temperature rise at medium-high rotational speed.

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 plus through oil holes on outer ring, can connect to centralized lubrication pipeline to supply lubricant without machine shutdown.

Important reminder: This 1:12 tapered bore NN-type double row cylindrical roller bearing with steel rollers supports on-site preload adjustment. Standard W33 groove on outer ring, ideal for equipment with centralized automatic lubrication system running continuously for long hours. 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. The double-row design provides higher rigidity and load capacity than single row cylindrical roller bearings of identical size. Suitable for heavy-duty precision machining spindles requiring frequent process adjustment, continuous uninterrupted lubrication and 24-hour non-stop operation.

Alternative variants:

NN3014 TN/SP (straight bore, no W33 groove, fixed preload, intermittent production with one-time greasing)

NN3014 TN/SPW33 (straight bore, W33 groove, fixed preload for continuous lubrication)

NN3014 KTN/SP (1:12 tapered bore, no W33 groove, adjustable preload, re-greasing only during shutdown)

NN3014 KTN/HC5SPW33 (1:12 tapered bore, hybrid composite rollers, higher limiting speed, reduced load capacity)

NN3014 KTN/UPW33 (1:12 tapered bore, UP ultra-precision grade for ultra-precision heavy-duty grinding spindles)

2 Structure & Operating Characteristics

NN 3014 KTN/SPW33 is an SP-grade precision double row cylindrical roller bearing with C1 minimal radial clearance, TN non-metallic cage, bearing steel rolling elements, 1:12 tapered bore and outer ring with built-in 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 advantage lies in adjustable preload via 1:12 tapered bore. Operators can increase or decrease preload by pushing the bearing axially with lock nut according to machining requirements, suitable for multi-product production lines with frequent process changes. The outer ring W33 lubrication groove connects centralized lubrication system to realize uninterrupted oil/grease supply during machine operation, perfect for 24-hour continuous manufacturing. The TN non-metallic cage controls frictional heat generation. Combined C1 minimal clearance and precision manufacturing tolerances restrain rotary vibration at medium-high speeds and stabilize finishing accuracy under heavy cutting loads.

Selection guide:

NN3014 KTN/SPW33 (1:12 tapered bore, adjustable preload, W33 groove, SP C1 clearance, continuous automatic lubrication, frequent process changes, all-day heavy-duty production)

NN3014 TN/SPW33 (straight bore, fixed preload, W33 groove, continuous lubrication, stable process without preload adjustment)

NN3014 KTN/SP (1:12 tapered bore, adjustable preload, no W33 groove, re-grease only during shutdown, intermittent production)

NN3014 TN/SP (straight bore, fixed preload, no lubrication groove, one-time grease filling during assembly)

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 for various heavy cutting conditions.

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. Outer ring W33 circumferential lubrication groove with oil holes supports continuous on-line lubricant replenishment for long-term non-stop production.

5. Lightweight TN non-metallic cage reduces friction loss and suppresses temperature rise during medium-high speed operation.

6. SP precision standard combined with C1 minimal radial clearance ensures tight control over rotational runout, reduces vibration and stabilizes surface finish under heavy cutting.

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 Spindle units of heavy-duty vertical machining centers running all day long

Multi-product processing, frequent parameter adjustment, equipped with centralized automatic oil/grease lubrication system

4.2 24-hour running medium-high speed CNC cylindrical & internal heavy-duty grinding precision spindles

Long continuous heavy-load grinding requiring uninterrupted on-line lubricant supply

4.3 Heavy-load precision CNC lathes and turn-mill composite spindles

Mass continuous production, frequent switching between roughing and finishing requiring spindle preload adjustment

4.4 Continuously operated heavy-duty precision rotary spindle equipment

High radial load demand, adjustable spindle rigidity, fitted with centralized automatic 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. Align outer ring W33 lubrication groove with housing oil passage during assembly to guarantee smooth lubricant flow. 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

Medium-high speed, heavy load, frequent process changes requiring on-site preload adjustment, machine equipped with centralized continuous automatic lubrication → NN3014 KTN/SPW33

Stable process without preload adjustment demand, continuous automatic lubrication environment → NN3014 TN/SPW33

Variable processes with adjustable preload, intermittent production, no continuous on-line oil supply, maintenance greasing only during shutdown → NN3014 KTN/SP

Intermittent production, fixed process without preload adjustment, one-time grease filling during assembly → NN3014 TN/SP

Higher limiting speed priority, medium load continuous machining → NN3014 KTN/HC5SPW33

Ultimate rotational accuracy, heavy-duty mirror continuous grinding → NN3014 KTN/UPW33

Important notice: Ensure smooth oil passage for W33 groove; filter contaminants to prevent oil hole blockage and local insufficient lubrication. 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. Centralized grease lubrication system can be connected to outer ring W33 channel for continuous operation. The lubrication structure allows lubricant replenishment without shutdown, yet regularly monitor oil supply pressure and flow rate. Continuously track bearing temperature; inspect blocked oil channels or improper preload once abnormal temperature rise appears. Compared with N1014 single row bearing of identical size, heat generation is higher at same rotational speed, regular inspection of lubrication system is necessary.

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. Filters should be installed on W33 lubrication pipelines to avoid contaminants entering the bearing with lubricant. Double-row rollers feature longer contact lines, pitting damage caused by impurities spreads faster, higher dust and coolant protection standard is required than single row bearings. Bearing steel rollers have good load and shock resistance, but long-term high-temperature operation accelerates lubricant ageing, so continuous operating temperature should be controlled within reasonable range.

6 Fault Identification

Common failure modes: steadily rising vibration during heavy cutting, regular texture patterns on machined workpieces, abnormal continuous spindle temperature increase, periodic rotational noise, cage abrasion & deformation, roller scuffing, raceway fatigue spalling, local dry friction overheating caused by blocked oil holes. Typical failures for tapered bore bearings: excessive preload leading to persistent overheating; insufficient preload resulting in reduced spindle rigidity and machining chatter marks; blocked W33 lubrication passages causing wear due to insufficient lubrication; uneven abrasion of two roller rows induced by unexpected axial loads; raceway spalling triggered by long-term overload and shock loads. 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.