RKS.21.0641 Slewing Bearings

RKS.21.0641 is a light series single row four point contact ball slewing bearing with an external gear, manufactured to the SKF RKS.21 standard. It features a flange on the inner ring for light weight and stable rotation. dm 641 mm, bore 534 mm, OD 742 mm (gear tip), height 56 mm; weighs 52 kg.

• Five-brand cross reference is the page moat: SKF RKS.21.0641 ↔ INA VLA200644-N ↔ Kaydon RK6-25E1Z ↔ Rollix 21-0641-01 ↔ Rothe Erde E.750.20.00.C / 231.20.0600 (laymachinery five-number mutual-recognition) — all five dims listed in 1 table; plus Schaeffler 88.0744.00 (NGW) as an extra.
• Made-in-China transparent price anchor: MICLuoyang Luoxin Industrial Cluster Zone lists "RKS.21.0641 Type" at US$98/pc (50-99 pcs tier) — the only openly-listed-price cross-validated by layered buyer tiers; sets the China-factory price expectation for filling-machine / construction-machinery OEMs.
• Light-series load-bearing sweet spot: C=200 kN / C0=440 kN + gear m6 z122 + tooth force 16/54 kN — enough for filling-machine + light excavator + bending robot; tipping-moment load only Light series can fit.
• Inner-ring flange signature (Light series, only 25% competitor coverage): "has flange on inner ring, has the feature of light weight and stable rotation" (Goldsupplier) — your page combines flange + light weight + stable rotation + Light Series quadruple keywords.
• Industry pioneer: tradebearings mistakenly tags 598 (inner-ring centring d1) as the third dimension — your page publishes "742 x 534 x 56 mm" per SKF catalogue and provides an integrity moat.
• Inch-explicit conversion: 534 mm = 21.02 in, 742 mm = 29.21 in, 56 mm = 2.20 in — matches ABMA / ANSI standards; complements mrosupply's 25 in / 33 1/9 in (0741) expression.
• Three-gear-type self-collision protection: external = RKS.21.0641 (this page, 52 kg), internal = RKS.22.0641 (48 kg), no gear = RKS.23.0641 (36.5 kg) — internal link anchors from M2 parameter table prevent cross-type cannibalisation in the same size family.
• Application-anchor evidence chain (six application scenarios addressable): Luoyang MIC "Packing Machine" + Coresun "Construction Machinery" + Changsha Gumi "Light Series Excavator" + Jinan Kaiming "Filling Machine" + ABF.store Europe stock + BSPD bearing spec — page collects 6 source evidence in 1 anchor.
• Light vs Medium interlock: RKS.061.20.0644 (D 742.8 mm / d 572 mm) is similar in OD but d-axle is different (572 vs 534); install-interchange must verify d1 / bolt circle before substitution (MIC conversion table evidence).

Product Description

RKS.21.0641 Slewing Bearings — Light Series External Gear Four-Point Contact Ball Turntable Bearing for Precision Industrial Applications

The RKS.21.0641 Slewing Bearings from Luoyang Heng Guan Bearing Technology Co., Ltd. is a light series, single-row, four-point contact ball slewing ring with an external gear. With a 742 mm OD, 534 mm bore, and 56 mm height, it weighs just 52 kg. Dynamic load rating C = 200 kN; static C0 = 440 kN. The inner-ring flange design delivers stable rotation with minimal weight penalty. Heng Guan Bearing is ISO9001 certified, exports to 50+ countries, and brings 30+ years of slewing bearing expertise to every order — from MOQ 1 pc to bulk supply.

Full Technical Specifications of RKS.21 0641 Slewing Ring

Accurate dimensions matter. Note that 598 mm is the inner-ring centring diameter (d1), not the bearing width — a common data error found on competing sites. The correct dimensions are 742 × 534 × 56 mm.

Parameter	Value
Mean raceway diameter dm	641 mm
Outside diameter D (incl. gear tip)	742 mm (29.21 in)
Inner diameter d	534 mm (21.02 in)
Total height H	56 mm ± 1 mm (2.20 in)
Weight	52 kg
Outer-ring centring diameter D2	642.5 mm
Inner-ring centring diameter d1	598 mm (centring Ø only)
Inner-ring inner diameter d2	639.5 mm
Outer-ring bolt pattern	16 × M12 threaded holes on Je = 685 mm PCD
Inner-ring bolt pattern	16 × Ø18 mm plain holes on Ji = 562 mm PCD
Gear pitch circle d0	732 mm
Gear module × teeth	m6 × z122 (pressure angle 20°)
Gear tooth force Tf normal / max	16 kN / 54 kN (3M cycles, normalized tooth)
Basic dynamic axial load rating C	200 kN
Basic static axial load rating C0	440 kN
Ball diameter	20 mm (four-point contact)
Ring material	C45E / 42CrMo4 / 50Mn
Raceway hardness	HRC 55–62 (induction hardened)
Seal	NBR integral seal, −40 ~ +110 °C
Lubrication	NLGI 2 lithium EP grease, 4 × AM8×1 fittings on inner ring
Speed limit	1.5 m/s continuous / 2.0 m/s short-time
Running accuracy radial / axial	≤ 0.2 mm / ≤ 0.3 mm

Cross-Reference & Interchange Guide for RKS.21.0641

If you're sourcing a direct replacement, the table below confirms dimensionally interchangeable models across major brands.

Brand	Model Number	Notes
SKF	RKS.21.0641	Reference standard
INA / Schaeffler	VLA200644-N	External gear, direct interchange
Kaydon	RK6-25E1Z	US market equivalent
Rollix	21-0641-01	European equivalent
Rothe Erde	E.750.20.00.C / 231.20.0600	Dimensional equivalent
Schaeffler (NGW)	88.0744.00	Cross-reference
No-gear version	RKS.23.0641 / INA VLU200644	Same family, no gear

Always verify d1 (598 mm) and bolt circle before substituting with similar OD bearings like RKS.061.20.0644 (OD 742.8 mm but bore 572 mm — not a drop-in replacement).

Key Product Advantages of the RKS.21 Light Series

This light series four-point contact ball slew ring offers a unique combination of compactness and load capability.

· Inner-ring flange design ensures light weight and stable rotation — a signature feature of the RKS.21 series rarely highlighted by competitors.

· Induction-hardened raceways at HRC 55–62 provide long fatigue life under cyclic loads.

· External gear m6 × z122 supports smooth meshing with driven pinions in packing machines and filling lines.

· NBR integral seal works reliably from −40°C to +110°C, protecting grease in outdoor and food-processing environments.

· Four relubrication fittings on the inner ring allow easy maintenance without disassembly.

· Running accuracy ≤ 0.2 mm radial / ≤ 0.3 mm axial suits precision turntable and robotic applications.

RKS.21.0641 Slewing Bearings factory

Typical Application Scenarios

You'll find this light series external gear turntable bearing working reliably across multiple industries.

· Packaging & filling machines — low-speed, smooth rotation for rotary fillers and capping turntables

· Construction excavator — light excavator swing mechanisms and compact crane slewing rings

· Bending robots & robotic arms — precise, repeatable rotation under moderate tipping moments

· Light-duty cranes & hoists — external gear engagement for driven rotation systems

· General OEM turntables — wherever a compact, 52 kg slewing ring with external gear fits your design envelope

Why Choose Heng Guan Bearing as Your China Manufacturer?

Luoyang Heng Guan Bearing Technology Co., Ltd. is based in Luoyang — China's recognized bearing manufacturing hub. We are proud to offer RKS.21.0641 Slewing Bearings. With 30+ years of experience and a team of 50+ engineers and technicians, we deliver precision you can count on.

· Diameter range: 50–10,000 mm; precision grades P0, P6, P5, P4

· Production equipment: CNC vertical lathes, CNC gear shapers, large gear hobbing machines, grinding machines, and quenching centers

· Quality control: Coordinate measuring machines, vibration testers, and life testing machines; full traceability from raw material to finished product

· ISO9001 certified; products comply with DIN, ISO, and GB standards; RoHS compliant

· Exported to 50+ countries including the USA, Germany, UK, Australia, Russia, and the Middle East

· Services: Technical consultation, product design, installation guidance, old product mapping, OEM/ODM, and non-standard customization

RKS.21.0641 Slewing Bearings certification

FAQ

Q1: What exactly is RKS.21.0641?

A: It is a light series, single-row, four-point contact ball slewing bearing with an external gear. It belongs to the SKF RKS.21 family, with dm 641 mm, 534 mm bore, 742 mm OD, and 56 mm height, weighing 52 kg.

Q2: What are the correct dimensions of RKS.21 0641?

A: Bore 534 mm (21.02 in), OD 742 mm (29.21 in), height 56 mm (2.20 in). Note: 598 mm is the inner-ring centring diameter — not the width. Gear pitch circle is 732 mm, module 6, 122 teeth.

Q3: Is RKS.21.0641 equivalent to INA VLA200644-N?

A: Yes. INA VLA200644-N, Kaydon RK6-25E1Z, Rollix 21-0641-01, and Rothe Erde 231.20.0600 are all dimensionally interchangeable. The non-geared equivalent is RKS.23.0641 / INA VLU200644.

Q4: What is the load capacity of this slewing ring bearing?

A: Dynamic axial load rating C = 200 kN; static C0 = 440 kN. Permissible gear tooth force is 16 kN normal and 54 kN maximum for the normalized gear tooth.

Q5: Is RKS.21.0641 available from stock?

A: Stock models typically ship within 3–7 business days. Non-stock standard models are produced in 25–30 days. Contact Us for current availability and factory-direct pricing.

Contact Us

Ready to order or need a quote? Email mia@hgb-bearing.com — MOQ 1 pc, fast delivery, competitive factory-direct pricing on RKS.21.0641 Slewing Bearings.

WHAT OUR CUSTOMERS SAY

Here is the customer's evaluation of us

From Europe

As a leading construction machinery manufacturer in Europe, we are very impressed with the quality and performance of your slewing rings. The precision machining and consistent quality meet our strict standards. A reliable global supplier!

From United States

Our CT scanners require extremely smooth rotation, low noise, and no magnetic interference. Your product perfectly meets these requirements, operating virtually silently without compromising image quality. Your technical expertise is truly impressive!

From Southeast Asia

We have been the distributor of your brand for many years and have received excellent customer feedback. Your diverse product line meets diverse customer needs, and our consistent quality makes us very competitive in the market. Your technical support and service team are also fantastic!

From United States

The slewing bearing selected for our wind turbine main drive system has exceeded our expectations in terms of precision and reliability. It operates smoothly even in extreme wind conditions and has a long maintenance cycle, significantly reducing our lifecycle costs. We are a trustworthy partner!

From the Middle East

Our equipment required a slewing bearing with non-standard dimensions and special gears. We contacted several companies but they all said they couldn't make it. Not only did you accept the order, but we also communicated smoothly throughout the entire process from proofing to mass production, and the finished product fully met our design requirements. This customization capability demonstrates your true technical strength.

From Europe

We have integrated your slewing rings into our new line of crawler cranes. The performance under full load and in extreme weather conditions has been flawless. The precision and durability meet the highest European standards. A truly reliable component for critical applications.

From North America

The harsh, sandy environment of our port is a true test for any equipment. Your slewing bearings' superior sealing system has effectively kept out abrasive contaminants. Our ship-to-shore cranes have seen a dramatic increase in uptime and service life since switching to your brand.

From the Middle East

In the mining industry, equipment failure is not an option. The immense strength and robust construction of your large-diameter slewing bearings have withstood the incredible shocks and loads in our mining excavators. Their reliability is directly contributing to our productivity.