The RA8008 cross roller bearing is a compact precision bearing with an 80 mm bore, 96 mm outside diameter and only 8 mm width. Its thin section and approximate 0.11 kg mass help reduce the size and rotating weight of small robot joints, optical stages and precision automation systems.
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 used as the rotating ring, while the separable outer ring requires accurate housing support.
LYDL supplies the RA8008 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, speed, accuracy, sealing and lubrication requirements for a drawing review and quotation.
RA8008 Cross Roller Bearing Overview
The RA8008 cross roller bearing provides an 80 mm through-bore within a 96 mm outside diameter.
Its width is only 8 mm, and its radial section is also only 8 mm. This makes RA8008 suitable for rotary mechanisms with strict size and weight limits.
Cylindrical rollers are arranged alternately at 90 degrees between the raceways. This arrangement supports radial load, axial load in both directions and overturning moment.
Spacer retainers separate adjacent rollers. They help reduce roller-to-roller friction and maintain stable rotational torque.
RA8008 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.
RA8008 Cross Roller Bearing Specifications
The principal RA8008 cross roller bearing dimensions and catalogue ratings are shown below.
Parameter
RA8008 specification
Bore diameter, d
80 mm
Outside diameter, D
96 mm
Width, B
8 mm
Radial section, (D − d) ÷ 2
8 mm
Roller pitch circle, dp
87 mm
Lubrication-hole reference, a × b
2 × 0.8 mm
Minimum corner radius, r min
0.5 mm
Maximum shaft shoulder, ds
83.5 mm
Minimum housing shoulder, Dh
90.5 mm
Basic dynamic radial load rating, C
6.37 kN
Basic static radial load rating, C0
11.3 kN
Approximate mass
0.11 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 radial, axial and moment loading.
Service life must be calculated from the real loads, speed, duty cycle, lubrication and required reliability.
Confirm the final LYDL drawing before machining the shaft, housing or retaining cover.
What Makes RA8008 Different?
Compact 80 mm Through-Bore
The RA8008 cross roller bearing provides an 80 mm opening for cables, a drive shaft, optical components or pneumatic lines.
Its 96 mm outside diameter keeps the surrounding robot joint or rotary stage compact.
Lightweight 0.11 kg Design
The bearing weighs approximately 0.11 kg. Low mass is useful in moving robot arms, inspection heads and other mechanisms where rotational inertia matters.
The surrounding housing must still be sufficiently rigid. A lightweight bearing should not be supported by a flexible cover plate.
Only 8 mm Radial Section
The difference between the bore and outside diameter is only 16 mm. This gives an 8 mm radial section on each side.
This geometry saves valuable installation space. It also makes the rings more sensitive to housing roundness and uneven clamping.
Multiple Loads in One Position
The crossed rollers allow RA8008 to support radial, bidirectional axial and moment loads.
This can reduce the need for separate radial and thrust bearings in a small rotary mechanism.
Typical RA8008 Cross Roller Bearing Applications
The RA8008 cross roller bearing is suitable for applications such as:
Small robot wrists and end effectors
Compact articulated robot joints
Optical and laser scanning stages
Semiconductor handling modules
Laboratory automation equipment
Precision camera and inspection gimbals
Measuring and calibration instruments
Small indexing and rotary tables
RA8008 is especially useful when designers need an 80 mm passage but cannot accommodate a thick bearing section.
The final selection should consider combined loads, moment arm, rotating mass, accuracy and installed torque.
For additional technical guidance, visit the LYDL Cross Roller Bearing Guide and Cross Roller Bearing Product Range.
Need an RA8008 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 RA8008 cross roller bearing configuration and provide a quotation with the controlled drawing.
RA8008 Variants and Suffixes
Suffix conventions can vary between manufacturers. Confirm the complete model and technical requirements before ordering.
Improves grease retention and contamination protection
RA8008C
Single-split alternative
Structure and availability require drawing confirmation
RA8008CUU
Single-split type with two seals
Confirm sealing drag and required 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 are useful when the bearing is exposed to dust or when grease retention is important. Seal contact may increase starting torque.
CC0 preload can improve rigidity and positioning stability. Excessive preload can increase friction, temperature and sensitivity to housing error.
An LYDL RA8008 cross roller bearing should be configured from the real application rather than by suffix alone.
Choose the RA5008 Cross Roller Bearing when a smaller 50 mm passage is sufficient.
Select the RA10008 Cross Roller Bearing when the mechanism requires a 100 mm bore.
RA8008 provides a useful middle option. It offers a larger passage than RA5008 without requiring the 116 mm outside diameter of RA10008.
Installation and Housing Requirements
The thin rings of the RA8008 cross roller bearing can follow errors in the surrounding structure.
Control housing roundness, shaft coaxiality, shoulder perpendicularity and retaining-cover flatness.
Use 83.5 mm as the catalogue maximum shaft-shoulder diameter. Use 90.5 mm as the catalogue minimum housing-shoulder diameter.
Confirm both values against the final LYDL drawing.
Clean the shaft, housing and cover before assembly. Remove burrs that could create local stress or misalignment.
Do not strike the rings or force the bearing into a distorted housing. The 0.11 kg thin-section bearing requires careful handling.
Tighten the outer-ring cover gradually in a diagonal sequence. Uniform clamping helps avoid local deformation of the separable outer ring.
After installation, rotate the inner ring slowly. Check torque, noise, smoothness and runout before connecting the motor.
Abnormal installed torque may result from:
Uneven cover-plate tightening
Housing roundness error
Misalignment between the shaft and housing
Excessive interference
Excessive preload
Seal friction
Contamination or excessive grease
These factors should be checked before identifying the bearing as the source of the problem.
Accuracy and Rotational Torque
Accuracy requirements should identify which ring rotates and which feature is being measured.
For RA8008, inner-ring rotation is normally preferred. Runout specifications should therefore be agreed using the complete assembly and inspection method.
A higher accuracy grade cannot compensate for a flexible housing or uneven outer-ring clamping.
Installed torque should be evaluated after the cover is fully tightened. Bench torque measured before installation may be lower.
For small motors and direct-drive stages, provide the available motor torque and allowable starting resistance during the selection stage.
Lubrication and Operating Conditions
Standard RA8008 versions normally use grease lubrication.
Grease viscosity and fill quantity should match the load, speed, temperature and required torque. Excessive grease can cause unnecessary resistance in a small precision mechanism.
The published −15°C to +80°C range relates to a standard grease configuration.
Vacuum, cleanroom, low-temperature or high-temperature applications require separate lubricant, seal and material confirmation.
Open bearings require a clean enclosure. Sealed versions improve protection but are not maintenance-free in every duty cycle.
LYDL Manufacturing and Quality Control
LYDL controls ring material, heat treatment, raceway grinding, roller sorting, clearance and final inspection according to the approved specification.
Inspection for an RA8008 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
Product marking and packaging
Special attention is given to roundness and torque because the bearing has only an 8 mm radial section.
Material certificates, dimensional reports and accuracy records can be supplied when agreed before production.
LYDL uses anti-rust protection and shock-resistant export packaging. The bearing is secured without applying concentrated pressure to the thin outer ring.
Interchange and Cross-Reference Guidance
RA8008 and IKO CRBS808 share nominal boundary dimensions of 80 × 96 × 8 mm.
However, published catalogue ratings differ. The standard IKO CRBS808 listing also has a different published mass from the RA8008 reference data.
Internal roller arrangement, clearance, accuracy, seals and lubrication details may also vary.
A matching size does 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 and moment
Speed and duty cycle
Lubrication and environmental conditions
LYDL will compare the existing product with the RA8008 cross roller bearing and issue a controlled drawing for approval.
RA8008 Cross Roller Bearing FAQ
1. How does RA8008 provide an 80 mm bore inside a 96 mm outside diameter?
The inner and outer rings use a very thin cross-section. The radial section is only 8 mm on each side.
This saves space but increases sensitivity to housing roundness and clamping accuracy.
2. Is RA8008 suitable for a lightweight robot wrist?
Yes, when the calculated loads, moment and rigidity are within the required limits.
Its approximate 0.11 kg mass helps reduce moving weight, while the crossed rollers support multiple load directions.
3. Can RA8008 replace two conventional bearings?
It can support radial, axial and moment loads in one bearing position.
Whether it can replace an existing bearing pair depends on load distribution, stiffness, speed, installation space and required service life.
4. Why can RA8008 torque increase after installation?
The thin outer ring can deform when the housing or retaining cover is inaccurate.
Uneven tightening, excessive interference, incorrect preload and seal friction can also increase torque.
5. Should an optical stage use C0 or CC0 clearance?
C0 may provide lower rotational resistance. CC0 can improve rigidity and reduce internal movement.
The correct choice depends on positioning accuracy, motor torque, temperature and mounting precision.
6. Can RA8008 operate continuously at high speed?
RA8008 is mainly selected for compact and accurate motion.
Continuous speed must be evaluated from load, preload, lubricant, seals, heat generation and available cooling.
7. Why do RA8008 and IKO CRBS808 have different load ratings?
The two products can share the same boundary dimensions while using different internal designs, roller complements and calculation data.
For this reason, load ratings from different brands should not be mixed during life calculations.
8. Is RA8008UU necessary inside a clean enclosure?
Not always. An open bearing may offer lower seal resistance when the mechanism already prevents contamination.
Choose UU when grease retention and additional environmental protection are more important than minimum torque.
Request an RA8008 Quotation
Send your application data or existing drawing to receive an RA8008 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 a faster technical response.
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.
