Closed End Needle Bearing BK1212 BK1212-RS BK121812 Roller Bearing 12x18x12mm

1.Product Overview

BK1212, BK1212-RS and BK121812 are metric single-row closed-end drawn cup needle roller bearings without inner ring, unified core dimension Fw=12mm roller assembly inner diameter, outer diameter D=18mm, total width C=12mm, differentiated by sealing structure and roller layout. BK series adopts integrated one-piece stamped steel outer cup with integral closed bottom cap, which provides automatic axial limit inside blind hole housings, removing extra snap rings, shaft shoulders and end covers to simplify assembly steps.

• BK1212: Standard 12mm width open type without rubber seal, excellent heat dissipation for clean, dry indoor working environments;
• BK1212-RS: 12mm width single-lip NBR RS contact rubber seal on open side, blocks fine dust, cutting fluid and light moisture for slightly polluted production workshops;
• BK121812: 12mm full thickened dense needle layout with no open gap, larger contact area to upgrade dynamic and static radial load capacity for heavy shock load conditions.

Stamped thin steel cage evenly separates dense needle rollers to achieve ultra-high radial bearing capacity under ultra-narrow radial cross-section. The matched installation shaft surface must be quenched and mirror superfinished to act as inner raceway. This series only bears pure radial load, widely used for miniature gearboxes, handheld power tools, textile tension rollers, automation blind hole sliding parts, micro hydraulic valves and light agricultural machinery shaft end positioning assemblies with strict radial space limits.

Get a quote within 24 hours for your project

2.Technical Specifications

Unified Base Standard Parameters

Fw (Needle assembly inner diameter): 12 mm
Outer Diameter D: 18 mm
Overall Width C: 12 mm
Structure: Single row closed end drawn cup needle bearing, no inner ring, stamped steel roller retainer
Material: Drawn cup & needle rollers GCr15 high-carbon chrome bearing steel
Standard Radial Clearance: CN normal clearance
Reference grease limiting rotation speed: 17200 r/min
Oil lubrication limiting rotation speed: 21600 r/min
Required matching shaft hardness: HRC60–64 with mirror superfinishing
Minimum chamfer r: 0.5 mm

BK1212

Sealing: Single closed bottom cap, open opposite end without seal
Dynamic Load Cr: 7250 N
Static Load Cor: 9480 N
Fatigue Load Limit Pu: 1360 N
Net Weight: 0.0068 kg

BK1212-RS

Sealing: Closed bottom cap + single RS contact rubber seal on open side
Dynamic Load Cr: 6980 N
Static Load Cor: 9130 N
Fatigue Load Limit Pu: 1310 N
Net Weight: 0.0071 kg

BK121812

Sealing: Fully enclosed thickened roller closed cup structure without open port
Dynamic Load Cr: 8360 N
Static Load Cor: 10750 N
Fatigue Load Limit Pu: 1520 N
Net Weight: 0.0075 kg
Complete dimensional drawings and full technical load data of three models are available upon customer request.

3.Key Advantages

1. Integrated closed end cap self-positioning design, directly pressed into blind hole housing without extra axial fixing parts, reducing component quantity and assembly labor cost
2. Ultra-thin radial cross-section minimizes equipment radial occupied space, perfectly meets miniaturized compact transmission structure design requirements
3. Three optional structural versions (open / single RS sealed / thickened heavy-load) cover mainstream working conditions: clean dry, damp dusty and heavy alternating shock load environments
4. Dense needle roller arrangement provides outstanding radial rigidity and load capacity, stable continuous medium-speed operation under frequent start-stop impact loads
5. Lightweight stamped steel cage ensures uniform roller guidance, low friction loss and efficient heat dissipation for long-cycle non-stop equipment operation
6. Customizable options include double-sided 2RS composite seals, C3 enlarged radial clearance, stainless steel anti-rust drawn cup, OEM laser marking and high-temperature wear-resistant grease filling

Effectively simplify blind hole housing machining processes and extend service life of shaft-end compact transmission assemblies

4.Applications

This BK1212 / BK1212-RS / BK121812 multi-spec closed end needle roller bearing set is widely matched for the following compact light & medium industrial equipment:

• Miniature reduction gearboxes, small transmission box blind hole shaft end supporting assemblies
• Handheld electric power tools, garden mini machinery and light agricultural rotary moving parts
• Textile weaving looms, small printing equipment tension sliding roller units
• Automation miniature linear sliding mechanisms and cam shaft positioning components
• Small hydraulic control valves, micro water pump lightweight rotary sliding assemblies
• Aftermarket replacement spare parts for 12mm inner diameter closed end drawn cup needle roller bearing equipment

Ideal multi-option high radial load bearing solution for blind hole shaft-end industrial transmission equipment with limited installation space

5.Why Choose GQZ Bearing

• 25 years of professional BK series closed end drawn cup needle roller bearing manufacturing experience
• Three models fully dimensionally interchangeable with international standard BK12 series bearings, consistent dimensional tolerance and load performance indicators
• Complete OEM & ODM customized service supporting double-sided sealing, stainless steel shell and special clearance customization
• Full-process strict inspection: raw material hardness testing, drawn cup stamping precision, sealing tightness and dynamic load fatigue cycle testing before delivery
• Professional bearing engineering team provides blind hole housing tolerance and matching shaft hardness installation guidance within 24 hours
• Stable large-scale mass production assembly lines with preferential bulk wholesale price for long-term machinery equipment manufacturers

We focus on reliable axial self-positioning performance, long service life and stable long-term win-win cooperation with global industrial buyers

6.Quality Control

• Raw material chemical composition and surface hardness inspection of GCr15 chrome bearing steel
• Precision deep drawing, trimming and forming processing for integrated closed end outer drawn cup
• Constant temperature heat treatment process to stabilize internal metal stress and enhance surface wear resistance
• Comprehensive performance testing: radial clearance uniformity, needle roller arrangement consistency, dynamic/static load capacity and RS seal dust-proof durability
• Uniform roller assembly inspection and separate dimensional & appearance re-inspection for each model before anti-rust packaging and shipment

Every batch of bearings passes full sampling reciprocating cycle durability test to guarantee stable heavy radial load operation in blind hole housings

7.Get a Quote Now

If you need high-quality BK1212 open type, BK1212-RS single sealed and BK121812 thickened heavy-load closed end drawn cup needle roller bearings for miniature gearbox and power tool equipment, send your inquiry to us directly.
You will receive full professional supporting services after submitting inquiry:

• Fast official factory quotation reply within 24 hours
• One-on-one blind hole housing tolerance & matching shaft hardness parameter matching guidance by professional bearing engineers
• Customized bearing solution suggestions including double RS sealed variants and stainless steel anti-rust drawn cup options
• Competitive direct factory bulk wholesale price for mixed three-model combined bulk orders

Send your required purchase quantity of each model and equipment operating environment to obtain detailed formal quotation

8.FAQ

Q1: What does suffix RS stand for in BK1212-RS?
A1: RS refers to single-lip NBR contact rubber seal installed at the open end of closed end bearing, used to block dust, coolant and light moisture.

Q2: What is the core difference between BK1212 and BK121812?
A2: Fw and outer diameter dimensions are fully consistent; BK121812 adopts thickened dense needle roller layout to greatly improve dynamic and static radial load rating, suitable for heavy-load impact working conditions.

Q3: Can BK series bearings operate without hardened ground shaft?
A3: Not recommended. The contact surface of the matching shaft must reach HRC60–64 quenching hardness with mirror superfinishing to serve as the inner raceway and avoid rapid bearing abrasion failure.