The RA14008 cross roller bearing is an ultra-thin precision bearing with a 140 mm bore, 156 mm outside diameter and only 8 mm width. Its large central opening can accommodate cables, optical paths, pneumatic lines or a hollow drive shaft without requiring a heavy bearing section.
Cylindrical rollers arranged alternately at 90 degrees allow one bearing position to support radial, bidirectional axial and overturning moment loads. The one-piece inner ring is normally selected as the rotating ring, while the separable outer ring requires uniform housing support.
LYDL supplies the RA14008 cross roller bearing in open, sealed, C0 and CC0 configurations. Higher accuracy, special grease, controlled clearance and inspection reports are available after technical confirmation.
Send your quantity, loads, moment, speed, accuracy, sealing and lubrication requirements for an LYDL drawing review and quotation.
RA14008 Cross Roller Bearing Overview
The RA14008 cross roller bearing provides a 140 mm through-bore within a 156 mm outside diameter.
Its width is only 8 mm. This combination is valuable when a rotary assembly needs a large central passage but has very limited axial space.
The difference between the bore and outside diameter is only 16 mm. The radial section is therefore 8 mm on each side.
Cylindrical rollers are arranged alternately at 90 degrees between the raceways. One bearing position can support radial, bidirectional axial and overturning moment loads.
Spacer retainers separate adjacent rollers. They help reduce roller-to-roller friction and maintain stable rotational torque.
RA14008 uses a one-piece inner ring and a separable outer ring. The inner ring is normally selected as the rotating ring when running accuracy is important.RA14008 combines a 140 mm through-bore with only 8 mm width for large-aperture precision rotary assemblies.
RA14008 Cross Roller Bearing Specifications
The principal RA14008 cross roller bearing dimensions and catalogue ratings are listed below.
Parameter
RA14008 specification
Bore diameter, d
140 mm
Outside diameter, D
156 mm
Width, B
8 mm
Radial section, (D − d) ÷ 2
8 mm
Roller pitch circle, dp
147 mm
Lubrication-hole reference, a × b
2 × 0.8 mm
Minimum corner radius, r min
0.5 mm
Maximum shaft shoulder, ds
143.5 mm
Minimum housing shoulder, Dh
150.5 mm
Basic dynamic radial load rating, C
8.33 kN
Basic static radial load rating, C0
19.1 kN
Approximate mass
0.19 kg
Ring structure
One-piece inner ring and separable outer ring
Standard lubrication
Grease lubrication
Standard-grease temperature range
−15°C to +80°C
The listed load ratings are basic radial catalogue values. They are not direct allowable limits for combined-load operation.
The large bore does not automatically make RA14008 a heavy-duty bearing. Its primary advantage is the large opening and thin section.
Bearing life depends on radial load, axial load, moment arm, speed, duty cycle, lubrication and required reliability.
Confirm the approved LYDL drawing before machining the shaft, housing or retaining cover.
What Makes RA14008 Different?
Large 140 mm Through-Bore
The RA14008 cross roller bearing provides a large passage for cables, optical components, air lines or a hollow transmission shaft.
It is suitable for equipment where components must pass through the center of rotation.
Only 8 mm Wide
RA14008 maintains an 8 mm axial width despite its 140 mm bore.
This leaves more installation space for motors, encoders, brakes, drive components or optical assemblies.
Approximately 0.19 kg
The bearing weighs approximately 0.19 kg.
Its low mass helps reduce rotary inertia in robot joints, optical positioning systems and lightweight automation modules.
Combined-Load Support
The crossed rollers support radial, bidirectional axial and moment loads in one bearing position.
This can simplify large-aperture rotary systems that would otherwise require separate radial and thrust bearings.
Higher Sensitivity to Housing Rigidity
The 156 mm outside diameter is large compared with the 8 mm bearing width.
The thin rings can follow housing or retaining-cover errors. Structural rigidity is therefore especially important.
Typical RA14008 Cross Roller Bearing Applications
The RA14008 cross roller bearing is suitable for:
Hollow-shaft robot elbows and shoulders
Semiconductor wafer-handling systems
Large-aperture optical positioning stages
Medical and laboratory positioning modules
Compact direct-drive rotary axes
Inspection and metrology platforms
Antenna and sensor pointing mechanisms
Cable-routing automation assemblies
The 140 mm bore provides space for larger cable bundles, optical paths or hollow transmission components.
RA14008 is most useful where opening diameter and installation thickness matter more than maximum load capacity.
For additional selection information, visit the LYDL Cross Roller Bearing Guide and Cross Roller Bearing Product Range.supports compact rotary motion in robot joints, optical stages, semiconductor equipment and inspection systems.
Need an RA14008 technical review? Send LYDL your quantity, radial load, axial load, moment load, speed and duty cycle.
Please include the rotating ring, accuracy, clearance or preload, sealing, lubricant and operating temperature.
We will review the RA14008 cross roller bearing configuration and provide a quotation with the controlled drawing.
RA14008 Variants and Suffixes
Suffix conventions can vary between manufacturers. Confirm the complete designation and technical requirements before ordering.
Improves grease retention and contamination protection
RA14008C
Single-split outer-ring type
Structure and mounting drawing must be confirmed
RA14008CUU
Single-split type with two seals
Confirm sealing drag and operating torque
C0
Standard or positive radial clearance
Generally favors lower rotational resistance
CC0
Controlled negative clearance or preload
Improves rigidity but increases mounting sensitivity
P6T / P5T
Specified rotational-accuracy options
Confirm the rotating ring and inspection method
P4 / P2 custom
LYDL high-precision option
Requires approved accuracy and inspection criteria
UU seals improve grease retention and provide additional contamination protection.
Seal contact can increase starting torque. Open bearings may be preferable inside clean equipment requiring minimum resistance.
CC0 preload can improve rigidity and positioning stability. Excessive preload can increase friction, temperature and housing sensitivity.
An LYDL RA14008 cross roller bearing should be configured according to the application rather than by suffix alone.
Short Brand Naming Guide
Different manufacturers may use different designations for a similar 140 × 156 × 8 mm bearing envelope.
Brand or supplier group
Common designation
Important note
THK
RA14008 / RA14008UU
Standard RA-series naming
IKO
CRBS1408, CRBS1408 A UU or CRBS1408 V
Internal structure and ratings vary by version
LYDL
RA14008, RA14008UU, RA14008UUCC0
Accuracy and clearance follow the approved order
Some aftermarket suppliers
XRA14008 or SRA14008
Supplier-specific prefix; drawing comparison is required
Similar designations do not guarantee identical load ratings, rollers, preload, accuracy or sealing.
Always compare the complete suffix and controlled drawing.
Choose the RA11008 Cross Roller Bearing when a 110 mm passage is sufficient and a smaller housing is preferred.
Select the RA12008 Cross Roller Bearing when a 120 mm bore provides enough routing space.
RA14008 should be selected when the mechanism requires the larger 140 mm opening. Its increased bore should not be used only to obtain a modest increase in load rating.
Installation and Housing Requirements
The thin rings of the RA14008 cross roller bearing closely follow the geometry of the surrounding structure.
Control housing roundness, shaft coaxiality, shoulder perpendicularity and retaining-cover flatness.
Use 143.5 mm as the catalogue maximum shaft-shoulder diameter. Use 150.5 mm as the catalogue minimum housing-shoulder diameter.
Confirm both dimensions against the final LYDL drawing.
The complete housing must be larger than the 156 mm bearing outside diameter.
Allow sufficient space for the housing wall, retaining cover and fasteners.
Because of the relatively large diameter, retaining-cover deflection must be controlled. Cover thickness and screw spacing should provide uniform support around the outer ring.
Clean all mating surfaces and remove burrs before installation. Do not force the bearing into a distorted housing.
Tighten the retaining screws gradually in a diagonal sequence. Uniform force helps prevent local outer-ring deformation.
After installation, rotate the inner ring slowly. Check torque, noise, smoothness and runout before connecting the drive.
Abnormal installed torque can result from:
Retaining-cover deflection
Uneven screw tightening
Housing roundness error
Shaft and housing misalignment
Excessive interference or preload
Seal friction
Excessive or unsuitable grease
These factors should be checked before identifying the bearing as defective.
Effective Bore and Cable Routing
The nominal bearing bore is 140 mm. The usable opening in the assembled machine may be smaller.
Shaft shoulders, fasteners, cable guides and surrounding components can reduce the final passage.
Check the complete assembly section before defining cable-bundle or optical-aperture dimensions.
Cables should be supported so that they do not contact the rotating ring or bearing seals.
Accuracy and Rotational Torque
RA14008 is normally used with inner-ring rotation.
Accuracy requirements should identify the rotating ring, measured surface and inspection method.
A high-accuracy bearing cannot compensate for a flexible housing or uneven outer-ring clamping.
Installed torque should be checked after the retaining cover reaches its final tightening condition.
For direct-drive equipment, provide the motor’s available starting torque before selecting seals or CC0 preload.
Lubrication and Operating Conditions
Standard RA14008 configurations normally use grease lubrication.
Grease viscosity and fill quantity should match the load, speed, temperature and required rotational resistance.
The published −15°C to +80°C range relates to a standard grease configuration.
Vacuum, cleanroom, low-temperature and high-temperature applications require separate grease, seal and material confirmation.
Open bearings require a clean enclosure. Sealed versions improve protection but are not maintenance-free under every duty cycle.
LYDL Manufacturing and Quality Control
LYDL controls ring material, heat treatment, raceway grinding, roller sorting, assembly clearance and final inspection.
Inspection for an RA14008 cross roller bearing can include:
Bore, outside diameter and width
Raceway geometry and surface condition
Radial clearance or preload
Inner-ring rotational runout
Starting and running torque
Noise and rotational smoothness
Seal condition and grease quantity
Marking and packaging inspection
Roundness, flatness and torque control are particularly important for a 156 mm bearing that is only 8 mm wide.
Material certificates, dimensional reports and accuracy records can be supplied when agreed before production.
LYDL uses anti-rust protection and shock-resistant export packaging. Concentrated pressure on the thin outer ring is avoided.dimensions, clearance, runout and rotational torque before protective export packaging.
Interchange and Cross-Reference Guidance
RA14008 and IKO CRBS1408 share nominal boundary dimensions of 140 × 156 × 8 mm.
Their published standard load ratings and mass are not identical. CRBS1408 variants can also use different retainers, separators or roller complements.
A matching bore, outside diameter and width do not prove complete interchangeability.
Before replacement, provide:
Existing manufacturer and complete model
All suffixes
Shaft and housing drawing
Required clearance or preload
Rotating ring
Loads, moment and speed
Lubrication and operating environment
LYDL will compare the existing product with the RA14008 cross roller bearing and issue a controlled drawing for approval.
RA14008 Cross Roller Bearing FAQ
1. Does the 140 mm bore make RA14008 a heavy-duty bearing?
No. RA14008 provides a large opening but remains only 8 mm wide.
Its load ratings must be checked against the real radial, axial and moment loads.
2. When should I choose RA14008 instead of RA12008?
Choose RA14008 when the mechanism needs a passage larger than 120 mm.
Do not increase the bearing size only for a small improvement in catalogue load rating.
3. Why is retaining-cover rigidity important?
The bearing has a 156 mm outside diameter but only 8 mm width.
A flexible cover can apply uneven pressure, causing local preload changes, torque variation and increased runout.
4. Is the complete 140 mm bore available for cables?
Not necessarily. The usable passage can be reduced by the shaft, shoulders, fasteners and cable guides.
Check the complete assembly drawing before defining the cable or optical path.
5. Can the outer ring rotate?
RA14008 is normally selected for inner-ring rotation because its outer ring is separable and housing-clamped.
For outer-ring rotation, evaluate an integrated-ring RAU design or another suitable structure.
6. Should a large optical stage use C0 or CC0?
C0 generally favors lower rotational resistance. CC0 can improve rigidity and reduce internal movement.
The correct choice depends on motor torque, positioning accuracy, temperature and housing stiffness.
7. Can RA14008 directly replace IKO CRBS1408?
The nominal dimensions match, but load ratings, mass and available internal configurations differ.
Compare clearance, accuracy, seals, lubrication and controlled drawings before replacement.
8. Why can different brands publish different load ratings?
Bearings with the same outer dimensions can use different roller complements, internal geometry and calculation data.
Life calculations should use the rating published for the exact selected product.
Request an RA14008 Quotation
Send your application data or existing drawing to receive an RA14008 cross roller bearing quotation.
LYDL can review open, sealed, clearance-controlled and customized precision configurations.
Provide quantity, loads, moment, speed, rotating ring, accuracy, clearance, sealing, lubricant and temperature for an efficient technical review.
ISO 492:2023 — geometrical product specifications and radial-bearing tolerances.
Engineering note: Catalogue values support preliminary selection only. Final life, fit, accuracy, clearance and interchangeability require complete application data and an approved LYDL drawing.
