Nn3012 Nn Series High Precision Bearing Cylindrical Roller Bearing for CNC Lathe

Product Description

NN Series Double Row Cylindrical Roller Bearings
Precision Grades P2 / P4 / P5  |  For Machine Tool Spindles & High-Precision Equipment
Luoyang Rock Precision Bearing Co., Ltd. 

1. Product Description
NN series bearings are double-row cylindrical roller bearings. The rollers are guided by the ribs on the inner ring. This design gives you high radial load capacity, high rigidity, and excellent running accuracy - exactly what you need for machine tool spindles, rotary tables, and other precision rotating equipment.
These bearings are separable. The inner ring (with rollers and cage) can be mounted separately from the outer ring. This makes installation and removal much easier, especially when both rings need an interference fit.
We supply both cylindrical bore and tapered bore (1:12, suffix K). The tapered bore lets you adjust radial clearance and preload using a locknut or adapter sleeve - standard practice for spindle applications.
Two main series are available: NN30 (medium cross-section) for general precision use, and NN49 (thin section) where radial space is limited. All bearings are made to ISO 492 standards, with precision grades from P5 up to P2.
2. Product Images

Figure 1 - NN series bearing with machined brass cage and tapered bore

 

Figure 2 - Cross-section: two rows of rollers, inner-ring guidance, brass cage, 1:12 tapered bore

3. Why Choose Our NN Bearings

• P2 / P4 / P5 Precision: Made to ISO 492 tolerances. P4 and P5 are standard stock items; P2 is made-to-order. Every bearing is 100% inspected before shipment.
• High Load Capacity: Two rows of rollers share the radial load. Compared to single-row bearings, you get significantly higher load rating in the same mounting space.
• High Rigidity: Low cross-section height plus a full set of rollers means minimal deflection under load. Your spindle stays stiff and accurate.
• High Speed: Optimized roller guidance and cage design allow high limiting speeds with grease or oil-air lubrication.
• Low Noise & Heat: Rollers are super-finished to Ra ≤ 0.05 μm. Raceways are precision ground. The result: less friction, less heat, longer service life.
• Easy Mounting: Separable design means you can fit the inner ring and outer ring independently. Great for arrangements with interference fits on both rings.
• Axial Float: The outer ring can move axially in both directions, so thermal expansion of the shaft won't cause binding.
• Cage Options: Machined brass (M), polyamide (TN), or pressed steel - we match the cage to your speed, load, and temperature requirements.
• Lubrication Groove: W33 option adds an oil groove and three oil holes in the outer ring for reliable oil delivery in high-speed or high-temperature applications.
• Tapered Bore: Suffix K (1:12 taper) lets you set preload and clearance precisely with a locknut - essential for precision spindle arrangements.

4. Technical Specifications

Item	Detail
Bearing Type	Double Row Cylindrical Roller Bearing (NN - inner ring rib guided)
Precision Grades	P2 / P4 / P5 (ISO 492)
Dimension Series	NN30 (medium), NN49 (thin section)
Bore Diameter	25 mm - 500 mm (larger sizes on request)
Bore Type	Cylindrical; Tapered 1:12 (suffix K)
Cage Material	Machined brass (M), Polyamide PA66-GF25 (TN), Pressed steel
Ring & Roller Material	GCr15 / SUJ2 / 100Cr6 bearing steel
Hardness	HRC 58 - 64 (rings and rollers)
Operating Temp.	-30 °C to +120 °C (standard); up to +250 °C with S1-S3 stabilization
Lubrication	Grease, oil bath, oil-air / oil-mist; W33 oil groove option
Radial Clearance	C1, C2, Normal, C3 (ISO 5753)
Roller Surface Finish	Ra ≤ 0.05 μm (super-finished)
Standards	ISO 492, ISO 5753, GB/T 307.1; ABEC/RBEC equivalent

5. How to Read the Part Number
Example: NN 3016 K / W33 / P4

Code	Meaning
NN	Double row cylindrical roller bearing; rollers guided by inner ring ribs (NNU = outer ring guided)
30	Dimension series: 30 = medium section; 49 = thin section
16	Bore code: 16 × 5 = 80 mm bore (codes 04-99)
K	Tapered bore, taper 1:12 (no K = cylindrical bore)
W33	Oil groove + 3 oil holes in outer ring
P4	Precision grade ISO Class 4 (also P2, P5)
M / TN	Cage: M = machined brass; TN = polyamide
C1/C2/C3	Radial clearance: C1 < C2 < Normal < C3
S1/S2/S3	Heat stabilized for +150 / +200 / +250 °C operation

6. Model & Dimension Table - NN30 Series
Below are common NN30 models. Load ratings and speeds are typical values. Need a model not listed? Send us your drawing or dimensions - we make non-standard bearings too.

Model	d	D	B	rs min	Cr	Cor	Grease	Oil-Air	Weight
NN3006	30	55	19	1.0	29	34	16000	19000	0.19
NN3007	35	62	20	1.0	36	44	15000	18000	0.22
NN3008	40	68	21	1.0	41.5	52	13000	16000	0.28
NN3009	45	75	23	1.0	50	62	12000	15000	0.36
NN3010	50	80	23	1.0	53	68	11000	14000	0.40
NN3011	55	90	26	1.1	65	82	10000	13000	0.58
NN3012	60	95	26	1.1	70	90	9500	12000	0.62
NN3013	65	100	26	1.1	76.5	98	9000	11500	0.68
NN3014	70	110	31	1.5	92	118	8500	10500	0.98
NN3015	75	115	31	1.5	98	128	8000	10000	1.05
NN3016	80	125	34	1.5	112	146	7500	9500	1.35
NN3017	85	130	34	1.5	118	156	7000	9000	1.45
NN3018	90	140	37	2.0	138	180	6500	8500	1.90
NN3019	95	145	37	2.0	145	192	6300	8000	2.00
NN3020	100	150	37	2.0	152	205	6000	7800	2.15
NN3022	110	170	45	2.1	190	260	5300	6800	3.20
NN3024	120	180	46	2.1	208	290	4800	6200	3.70
NN3026	130	200	52	2.1	245	340	4300	5600	5.10
NN3028	140	210	53	2.1	260	365	4000	5200	5.60
NN3030	150	225	56	2.1	290	410	3700	4800	6.80
NN3032	160	240	60	2.1	320	455	3400	4400	8.20
NN3036	180	280	74	2.5	410	590	2900	3800	12.5
NN3040	200	310	82	2.5	480	690	2500	3300	17.8

Units: d, D, B, rs in mm; Cr, Cor in kN; speeds in rpm; weight in kg. Speeds are reference values for standard grease / oil-air lubrication at normal temperatures. Actual speed depends on load, preload, lubrication, and cooling.
7. Precision Grade Comparison
We offer three precision grades per ISO 492. The table below shows representative tolerance values for bore diameter d = 50-80 mm (NN3011 to NN3016). Values vary by diameter range - contact us for exact tolerances for your specific model. Tighter tolerances mean lower runout and better machining accuracy.

Parameter	P5	P4	P2	Unit
Bore dia. variation (Δdmp)	0 / -10	0 / -6	0 / -3	μm
OD variation (ΔDmp)	0 / -12	0 / -8	0 / -4	μm
Inner radial runout (Kia)	6	3	1.5	μm
Outer radial runout (Kea)	7	3.5	2	μm
Inner axial runout (Sia)	8	4	2	μm
Outer axial runout (Sea)	9	5	2.5	μm
Width variation (VBs, max)	8	5	2.5	μm
Typical Use	General precision spindles, motors, gearboxes	CNC machining centers, high-precision spindles	Ultra-precision grinding, aerospace, metrology	-

8. Materials & Construction
8.1 Bearing Steel
Rings and rollers are made from GCr15 (SUJ2 / 100Cr6) high-carbon chromium bearing steel. We buy steel from certified mills only. Every batch comes with a material certificate showing chemical composition, hardness, and inclusion rating. Heat numbers are tracked from raw steel to finished bearing.
8.2 Heat Treatment
Rings and rollers are martensitic quenched and tempered to HRC 58-64. Retained austenite is controlled for maximum fatigue life. For high-temperature applications, we offer S1 (+150 °C), S2 (+200 °C), and S3 (+250 °C) heat stabilization so the bearing won't lose precision under heat.
8.3 Cage Options

Cage	Suffix	Material	Best For
Machined brass	M	CuZn39Pb3	Heavy loads, high temp, aggressive oils - strongest and most durable
Polyamide	TN	PA66-GF25	High speed, low friction, lightweight - up to +120 °C
Pressed steel	-	Low-carbon steel	Cost-effective for standard-load, moderate-speed use

8.4 Surface Finish
Roller surfaces are super-finished to Ra ≤ 0.05 μm. Raceways are ground to Ra ≤ 0.1 μm. Smooth surfaces mean less friction, less noise, and longer life - especially important in high-speed spindles where lubrication film is thin.
8.5 Available Options

• W33 - oil groove and 3 oil holes in outer ring
• K - 1:12 tapered bore for preload adjustment
• S1 / S2 / S3 - heat stabilized for high temperatures
• C1 / C2 / C3 - special radial clearance classes
• Phosphating, black oxide, or anti-rust coating for corrosion protection
• Custom dimensions and non-standard designs - send us your drawing

9. Where These Bearings Are Used

• Machine tool spindles - CNC lathes, machining centers, boring mills
• Precision grinding machines - surface, cylindrical, tool & cutter grinders
• Rotary tables and indexing heads
• Industrial gearboxes and speed reducers (high-speed input shafts)
• Electric motors, generators, and turbo machinery
• Rolling mills - work rolls, back-up rolls, pinch rolls
• Mining and construction machinery
• Paper and printing machinery - calendar rolls, dryer cylinders, printing cylinders
• Textile machinery - high-speed spinning and twisting spindles
• Medical equipment requiring high rotational accuracy

10. Quality Control & Certifications
10.1 Our Certifications

Certification	What It Covers	What It Means for You
ISO 9001:2015	Quality management system	Consistent quality, documented processes, continuous improvement
ISO 14001:2015	Environmental management	Responsible manufacturing, regulatory compliance
IATF 16949	Automotive quality (applicable lines)	Automotive-grade process control, PPAP/APQP capability
RoHS / REACH	Hazardous substance restriction	EU compliance - safe to sell and distribute globally

10.2 How We Inspect Every Bearing
Quality is checked at every step, not just at the end:

• Raw material: spectrometer checks chemical composition; hardness and inclusion rating verified per heat number.
• Forging & turning: 100% dimensional check on blanks; SPC monitoring on turned dimensions.
• Heat treatment: hardness tested every batch; microstructure and case depth verified.
• Grinding: in-process gauging of bore, OD, width, and raceways; roundness measured on a roundness meter; roughness checked with a profilometer.
• Assembly: clean room assembly; rollers sorted by diameter within 0.5 μm; clearance and preload verified.
• Final inspection: 100% dimensional and runout check per ISO 492; noise and vibration tested; surface defects inspected visually; rotational torque checked.
• Traceability: every bearing has a laser-marked part number and batch code. Records from raw steel to finished product are kept for at least 5 years.

10.3 Inspection Equipment

• Roundness / cylindricity measuring instrument (0.02 μm resolution)
• Profile projector and optical measuring microscope
• Surface roughness tester (Ra / Rz)
• Bearing vibration analyzer (low / medium / high frequency)
• Noise testing chamber
• Rockwell and Vickers hardness testers
• Metallurgical microscope
• Optical emission spectrometer
• Clean room assembly area (Class 10,000 / ISO 7)
• Coordinate Measuring Machine (CMM)

11. Packaging & Shipping
11.1 Export Packaging
1. Each bearing is individually wrapped in VCI anti-rust paper.
2. Wrapped bearings go into labeled plastic tubes or individual boxes with part number, quantity, and batch code.
3. Boxes are packed into double-wall corrugated cartons with a packing list and desiccant.
4. Cartons are secured on ISPM 15 fumigated wooden pallets with stretch wrap and steel strapping.
5. Neutral (unbranded) or custom-branded packaging available on request.
11.2 Order & Delivery Terms

Item	Detail
MOQ	No strict MOQ for standard models. Sample orders (1-10 pcs) welcome.
Lead Time - Standard	7-15 working days (subject to stock)
Lead Time - Custom / Large	20-45 working days depending on quantity and spec
Samples	Free samples for established buyers; freight collect or prepaid
Incoterms	EXW, FOB, CIF, CFR, DDP - all supported
Loading Ports	Shanghai, Ningbo, Qingdao, Shenzhen
Payment	T/T (30% deposit, 70% before shipment), L/C at sight, Western Union, Trade Assurance
Shipping	Sea (LCL/FCL), air, express (DHL / FedEx / UPS)

12. Our Advantages

• Factory direct: Based in Luoyang - China's historic bearing manufacturing hub. We make these bearings in-house: forging, turning, heat treatment, grinding, super-finishing, and assembly. No middlemen, better prices, full process control.
• Precision specialist: We focus on P2 / P4 / P5 super-precision cylindrical roller bearings for machine tool and high-end industrial use. This is not a side product for us.
• 100% final inspection: Every bearing is checked for dimensions, runout, noise, and vibration before it leaves the factory. ISO 9001 certified. Full material traceability.
• Custom engineering: Our R&D team can design and make non-standard bearings to your drawing - special dimensions, materials, coatings, or clearance configurations.
• Reliable supply: We keep buffer stock for standard models so lead times stay short. Steel comes from certified mills with long-term supply agreements.
• Global export experience: We ship to 50+ countries across Europe, the Americas, Asia, and the Middle East. We know the documentation and standards you need.
• Fast technical support: Our engineers reply within 24-48 hours with selection help, mounting guidance, lubrication advice, and failure analysis.
• Flexible terms: Small batches and samples accepted. Mixed container loading available. OEM / private labeling supported with confidentiality agreements.

13. FAQ
Q: What is the difference between NN and NNU?
A: NN bearings have rollers guided by the inner ring ribs. NNU bearings have rollers guided by the outer ring ribs. NN is more common for machine tool spindles because the inner ring (on the rotating shaft) gives better roller guidance at high speed. NNU is used when the outer ring rotates or the inner ring needs frequent removal.
Q: Can you make P2 grade? How long does it take?
A: Yes, P2 is available for most NN30 and NN49 sizes. P2 requires extra grinding and super-finishing, so lead time is usually 25-45 working days. Contact us early for P2 projects so we can check availability and schedule.
Q: Do you do OEM / private label?
A: Yes. We can put your brand name, logo, and part number on the bearing (laser marking) and use your custom packaging. All OEM work is covered by a confidentiality agreement - we never share your information.
Q: What is your minimum order quantity?
A: There is no strict MOQ for standard catalog models. You can order 1 piece for testing. Unit price is higher for small quantities, of course. For custom or non-standard bearings, MOQ is typically 10-50 pieces depending on size.
Q: How do you guarantee precision grade consistency?
A: We control precision at every step: SPC during grinding, 100% in-process gauging, roller sorting within 0.5 μm, and 100% final inspection of bore, OD, runout, and width. We can provide an inspection report (COC) with every shipment if you need it.
Q: Can these bearings run at high temperatures?
A: Standard bearings are good for continuous use up to +120 °C. For higher temperatures, we offer S1 (+150 °C), S2 (+200 °C), and S3 (+250 °C) heat-stabilized versions. At high temperatures, cage material and lubricant become critical - ask our engineers for a recommendation.
Q: What lubrication do you recommend for high-speed spindles?
A: For maximum speed, oil-air or oil-mist lubrication is best - it delivers a small, precise amount of oil right to the contact zone. For moderate speeds, high-speed spindle grease (lithium complex or polyurea thickened synthetic oil) works well. Bearings with the W33 option are designed for oil-air / oil-mist lubrication. Always follow your machine builder's specification.
Q: Do you provide inspection certificates?
A: Yes. Every shipment can include a Certificate of Conformity (COC) confirming the ordered precision grade and specification. For an extra fee, we can provide detailed dimensional inspection reports (measured values for each parameter) and material test certificates (EN 10204 3.1 / 3.2) from the steel mill.
14. Contact Us
Send us your inquiry - part number, quantity, and any special requirements. We'll get back to you within 24 hours with a quotation and technical recommendation.

Item	Detail
Company	Luoyang Rock Precision Bearing Co., Ltd.
Address	No.11, Dongmagou Industrial Park, Jianxi District, Luoyang City, Henan Province, P.R.China
Contact	Eleven

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Note: Dimensions, load ratings, and speeds are typical reference values. Actual performance depends on specific model, lubrication, mounting, and operating conditions. Please confirm exact data with us before ordering.