| Brand Name: | NSK |
| Model Number: | 708AT |
The FUJI NSK 708ATYNDBMP5 H4218K precision bearing is designed for selected motion assemblies used in FUJI electronic component placement equipment. It is commonly referenced as a replacement bearing for specific FUJI NXT and XP143 configurations, although the exact installation axis or mechanical module should always be confirmed through the machine parts manual, assembly drawing, or removed bearing marking.
This compact angular contact ball bearing features an 8 mm inner diameter and a 22 mm outer diameter. The full NSK designation identifies a polyamide cage, back-to-back matched bearing arrangement, medium preload, and P5 precision class. These features make the bearing suitable for applications requiring controlled rigidity, accurate rotational guidance, and stable movement under combined radial and axial loads.
The bearing is intended for professional SMT machine repair, scheduled preventive maintenance, mechanical module rebuilding, and replacement of worn motion-system components. Correct installation helps maintain smooth movement, consistent positioning, and dependable production performance.
The verified commercial cross-reference connects NSK 708ATYNDBMP5 with FUJI spare-part reference H4218K. Public equipment listings associate the part with FUJI electronic-component mounting equipment, including selected NXT and XP143 applications. Because FUJI machine revisions may use different bearing arrangements, final compatibility must be checked before ordering.
| Identification Item | Product Information |
|---|---|
| Product Category | Precision Angular Contact Ball Bearing |
| Equipment Brand Reference | FUJI |
| Bearing Manufacturer | NSK |
| Full Bearing Model | 708ATYNDBMP5 |
| FUJI Part Number | H4218K |
| Simplified Search Model | 708AT |
| Bore Diameter | 8 mm |
| Outside Diameter | 22 mm |
| Bearing Arrangement | Back-to-Back Matched Set |
| Preload Level | Medium Preload |
| Accuracy Class | P5 |
| Cage Type | Polyamide Cage |
| Main Application | SMT Mounter Motion Assembly |
| Referenced Machine Families | Selected FUJI NXT and XP143 configurations |
| Installation Position | Confirm according to machine BOM and assembly drawing |
| Ordering Unit | Set or piece according to actual package marking |
The NSK designation system identifies TYN as a polyamide cage, DB as a back-to-back duplex arrangement, M as medium preload, and P5 as a precision class. Back-to-back angular contact bearing arrangements can support radial loading and axial loading from both directions while providing higher moment rigidity than a face-to-face arrangement.
Precision bearings operate continuously inside high-speed SMT placement equipment. Even when a bearing does not show visible external damage, its internal raceways, rolling elements, cage, lubrication condition, or preload relationship may gradually deteriorate.
A worn or incorrectly installed bearing can affect the stability of the motion assembly and may create positioning errors that appear to originate from a motor, encoder, ball screw, guide rail, or control system.
| Cause | Possible Mechanical Effect |
| Extended operating hours | Raceway fatigue and gradual increase in vibration |
| Insufficient lubrication | Higher friction, heat generation, and abnormal noise |
| Contaminated grease | Surface damage to balls and raceways |
| Dust or foreign particles | Irregular rotation and accelerated wear |
| Incorrect mounting force | Brinelling, deformation, or preload variation |
| Incorrect bearing orientation | Reduced axial support and unstable motion |
| Excessive belt or screw load | Abnormal radial or axial loading |
| Shaft misalignment | Uneven contact and localized raceway wear |
| Repeated machine collision | Impact damage and reduced rotational accuracy |
| Improper storage | Corrosion, grease deterioration, or contamination |
| Mixing unmatched bearings | Inconsistent preload and reduced system rigidity |
| Incorrect replacement model | Dimensional or performance mismatch |
Maintenance personnel may consider inspecting the bearing when one or more of the following conditions appear:
These symptoms do not automatically prove that the bearing is defective. Motors, couplings, ball screws, belts, pulleys, guide rails, encoders, shafts, and mounting seats should also be inspected before the final repair decision.
Replacing a worn bearing with the correctly identified NSK 708ATYNDBMP5 H4218K helps restore the intended support and guidance of the affected FUJI mechanical assembly.
Unlike an ordinary general-purpose bearing, this model uses a matched angular contact configuration with controlled preload and precision accuracy. The matched arrangement is important because the bearing pair must work as one mechanical system. Installing an unmatched bearing with a different preload, cage, tolerance, or contact arrangement may change axis rigidity and running behavior.
| Maintenance Requirement | Product Solution |
| Restore smooth rotational movement | Precision raceways and matched rolling elements |
| Support combined mechanical loads | Angular contact ball-bearing construction |
| Improve assembly rigidity | Back-to-back bearing arrangement |
| Control internal operating clearance | Factory-defined medium preload |
| Reduce unnecessary movement | P5 precision accuracy |
| Maintain repeatable axis response | Stable rotational guidance |
| Simplify part identification | Full NSK model and FUJI cross-reference |
| Support preventive maintenance | Suitable for planned bearing replacement |
| Reduce incorrect substitutions | Exact suffix identification |
| Improve procurement accuracy | H4218K and 708ATYNDBMP5 cross-reference |
The simplified description “708AT” is not sufficient for accurate replacement procurement. Bearings sharing the same basic 708 series can have different cage materials, preload levels, matching arrangements, internal clearances, and accuracy grades.
For this reason, inquiries and purchase orders should specify:
NSK 708ATYNDBMP5 / FUJI H4218K
Using the complete model helps prevent substitution with a bearing that has the correct physical size but the wrong operating characteristics.
| Specification | Description |
| Product Name | Precision Angular Contact Ball Bearing |
| Equipment Reference | FUJI SMT Mounter |
| Manufacturer | NSK |
| Full Model Number | 708ATYNDBMP5 |
| FUJI Reference Number | H4218K |
| Bearing Series | 708 |
| Bearing Type | Angular Contact Ball Bearing |
| Bore Diameter | 8 mm |
| Outside Diameter | 22 mm |
| Width | Confirm by NSK drawing or removed bearing |
| Rolling Element | Precision Steel Balls |
| Ring Material | Bearing Steel |
| Cage Design | TYN Polyamide Cage |
| Arrangement Code | DB, Back-to-Back Duplex |
| Preload Code | M, Medium Preload |
| Accuracy Code | P5 Precision Class |
| Load Capability | Combined radial and axial loads |
| Axial Load Direction | Both directions when used as the matched DB set |
| Mechanical Feature | High rigidity and controlled rotational guidance |
| Primary Industry | Electronics Manufacturing |
| Equipment Type | SMT Pick-and-Place Machine |
| Application Reference | Selected FUJI NXT and XP143 assemblies |
| Operating Environment | Industrial electronic assembly line |
| Installation Method | Professional mechanical installation required |
| Lubrication | Follow original machine and bearing requirements |
| Condition | New unless otherwise stated in quotation |
| Packing | Protective individual or matched-set packaging |
| Compatibility Rule | Confirm by BOM, bearing marking, and machine revision |
| Warranty | Subject to quotation and supply condition |
The 8 mm bore and 22 mm outer diameter are supported by available trade and product-identification records for NSK 708ATYNDBMP5. However, bearing width, installation direction, matching marks, preload orientation, lubrication method, and exact machine axis should be confirmed against the original bearing and FUJI service documentation before installation.
| Model Code | Technical Meaning |
| 708 | Compact angular contact bearing series with 8 mm bore reference |
| A | Angular contact design designation |
| TYN | Polyamide cage |
| DB | Back-to-back duplex matched arrangement |
| M | Medium preload |
| P5 | Precision accuracy class |
| H4218K | FUJI spare-part cross-reference |
The suffixes are essential to product selection. A standard 708 bearing without the correct matching, preload, cage, and precision codes should not automatically be considered an equivalent replacement.
The product is identified by the complete NSK designation 708ATYNDBMP5 rather than only the shortened 708AT reference. This helps purchasing teams compare quotations correctly and reduces the risk of ordering a visually similar but technically different bearing.
The DB arrangement positions the bearing pair back-to-back. This structure provides support for radial loads, axial loads in both directions, and moment loads generated by the machine mechanism.
The M suffix indicates medium preload. Preload reduces unwanted internal movement and increases assembly rigidity, supporting more stable mechanical guidance.
The P5 designation is intended for applications requiring greater dimensional and running accuracy than ordinary industrial bearings. This is important in SMT machinery where repeatable mechanical movement affects production stability.
The compact bearing size is suitable for precision motion assemblies where installation space is limited and accurate shaft support is necessary.
The H4218K cross-reference supports faster identification for FUJI equipment maintenance, spare-parts inventory, machine rebuilding, and emergency replacement.
Displaying both the NSK bearing model and FUJI part number allows maintenance engineers, distributors, and purchasing departments to cross-check the same item using different documentation systems.
The bearing can be stocked as part of a planned maintenance program to reduce delays when vibration, noise, or mechanical wear is detected.
The FUJI NSK 708ATYNDBMP5 H4218K is intended for precision mechanical assemblies in electronic-component placement equipment.
| Application Area | Function |
| FUJI SMT Mounter Maintenance | Replacement of worn precision bearing sets |
| Selected NXT Assemblies | Motion-system bearing support, subject to BOM confirmation |
| Selected XP143 Assemblies | Mechanical axis or head-related support, subject to revision |
| Axis Rebuilding | Restoration of shaft support and rotational guidance |
| Mechanical Module Repair | Replacement during component-level overhaul |
| Preventive Maintenance | Scheduled replacement before serious failure |
| Used Machine Refurbishment | Restoration of mechanical operating condition |
| Production Line Spare Stock | Emergency inventory for maintenance teams |
| Service Department Inventory | Standardized bearing identification |
| SMT Equipment Resale Preparation | Mechanical inspection and maintenance |
The H4218K bearing is publicly marketed for selected FUJI NXT and XP143 equipment, but individual machine generations, serial-number ranges, mechanical revisions, and axis assemblies may differ.
Before ordering, the buyer should provide at least one of the following:
Angular contact ball bearings use raceways that are offset relative to each other. The contact line between the balls and raceways is positioned at an angle to the radial plane. This allows the bearing to support radial loading together with axial loading.
A single angular contact bearing normally supports axial force primarily in one direction. In a back-to-back matched set, two bearings are installed in opposing directions. The pair can therefore support axial forces from both directions and provide improved resistance to overturning moments.
| Stage | Bearing Function |
| 1. Motor or mechanism begins moving | Shaft transfers rotational or motion-related load |
| 2. Inner ring rotates or supports the shaft | Rolling elements move along precision raceways |
| 3. Radial load enters the bearing | Balls distribute the load through the raceway contact points |
| 4. Axial load is generated | Angular contact geometry transfers thrust through the bearing |
| 5. Opposing bearing supports reverse thrust | DB arrangement controls axial force in both directions |
| 6. Medium preload removes excess clearance | Mechanical rigidity and response are stabilized |
| 7. P5 accuracy controls running behavior | Rotation remains more consistent and repeatable |
| 8. Lubrication separates contact surfaces | Friction, wear, and heat generation are reduced |
A back-to-back bearing pair has a relatively wide distance between its effective load centers. This provides stronger moment-load capability and supports a rigid mechanical arrangement.
For SMT equipment, this can contribute to:
Preload applies a controlled internal force to the matched bearing set before the external operating load is introduced.
The intended effects include:
Preload should not be added arbitrarily during installation. The bearing set already has a specified matched condition, and excessive assembly pressure may create abnormal heat, torque, or premature failure.
Installation should be performed by a technician familiar with precision bearing handling and FUJI equipment maintenance.
| Inspection Item | Acceptance Check |
| Manual Rotation | Smooth movement without sticking |
| Abnormal Noise | No scraping, clicking, or rough sound |
| Axial Movement | Within the machine’s specified range |
| Temperature | No rapid abnormal temperature increase |
| Servo Load | Stable compared with normal machine condition |
| Calibration | Completed successfully |
| Motion Test | Smooth acceleration and deceleration |
| Production Trial | Stable operation under controlled test conditions |
| Fastener Check | Correctly tightened and secured |
| Lubrication Check | Correct type and quantity applied |
Choosing a bearing only by outer appearance or basic dimensions is not recommended. The complete suffix affects internal construction and performance.
| Selection Point | Required Confirmation |
| Equipment Brand | FUJI |
| Machine Model | NXT, XP143, or other confirmed model |
| Machine Serial Number | Recommended for revision checking |
| FUJI Part Number | H4218K |
| NSK Model | 708ATYNDBMP5 |
| Bore Diameter | 8 mm |
| Outside Diameter | 22 mm |
| Arrangement | DB back-to-back matched set |
| Preload | M medium preload |
| Precision | P5 |
| Cage | TYN polyamide |
| Quantity | Confirm whether one matched set or individual piece |
| Installation Axis | Confirm from parts manual |
| Condition Required | New or another agreed condition |
| Packaging | Original or protective industrial packaging |
| Delivery Requirement | Standard or urgent shipment |
For faster and more accurate quotation, send:
| Information | Example |
| Product Name | FUJI precision bearing |
| FUJI Part Number | H4218K |
| Bearing Model | NSK 708ATYNDBMP5 |
| Machine Model | FUJI NXT or XP143 |
| Machine Serial Number | Provide from machine label |
| Installation Position | X-axis, Z-axis, head, or module name |
| Quantity | Number of pieces or matched sets |
| Required Condition | New |
| Destination Country | Import destination |
| Delivery Deadline | Required arrival date |
| Product Photo | Bearing and package markings |
| Additional Parts | Shaft, housing, screw, belt, or motor |
Before shipment, the bearing should be checked according to the agreed supply condition.
| Inspection Item | Inspection Purpose |
| Model Marking | Confirm 708ATYNDBMP5 |
| Part Cross-Reference | Confirm H4218K |
| Package Label | Verify manufacturer and model |
| Bearing Surface | Check for rust, dents, or contamination |
| Rotation Condition | Confirm smooth manual rotation |
| Pair Identification | Confirm matched bearing relationship |
| Dimensions | Verify critical installation dimensions |
| Cage Condition | Check visible cage damage |
| Packing Protection | Prevent moisture and impact |
| Quantity | Confirm pieces or matched sets |
| Photo Record | Support shipment verification |
| Final Label | Prevent warehouse picking errors |
The complete NSK bearing model is 708ATYNDBMP5. “708AT” is only a shortened reference and does not show the cage, matched arrangement, preload, or precision class. Purchase orders should use the full model number together with FUJI part number H4218K.
No. Public spare-parts listings associate H4218K with selected FUJI NXT and XP143 applications, but the exact axis, mechanical module, serial-number range, and machine revision may differ. Compatibility should be confirmed by the original bearing marking, FUJI BOM, or service manual.
DB indicates a back-to-back matched bearing arrangement. M indicates medium preload, and P5 indicates a precision accuracy class. These suffixes affect rigidity, operating clearance, and running accuracy, so they should not be omitted when selecting a replacement.
A standard 708 bearing should not be treated as an automatic replacement. It may have a different contact design, cage, preload, matching arrangement, or precision grade. Even when the external dimensions appear similar, the machine’s motion performance may be different.
Please provide the full bearing marking, FUJI part number, machine model, serial number, installation position, required quantity, product condition, and destination country. A photograph of the removed bearing and package label is strongly recommended for final verification.
Looking for a reliable FUJI H4218K bearing for SMT machine maintenance?
Send us your machine model, serial number, required quantity, installation position, and a clear photo of the removed bearing. Our team will cross-check the NSK 708ATYNDBMP5 identification before quotation and help reduce the risk of ordering an incorrect specification.
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Contact SMT PARTS SUPPLY LTD. today for availability, pricing, delivery time, and technical confirmation.
| Inquiry Field | Customer Information |
| Required Product | FUJI NSK 708ATYNDBMP5 H4218K Bearing |
| Machine Model | |
| Machine Serial Number | |
| Installation Position | |
| Quantity | |
| Required Condition | |
| Destination Country | |
| Delivery Deadline | |
| Removed Bearing Photo | Attached / Not Attached |
| Additional Requirements |
FUJI and NSK names, machine models, and part numbers are used only for product identification and compatibility reference. This product page does not imply sponsorship, authorization, or affiliation unless specifically stated in the commercial quotation.
Machine compatibility can vary by production year, serial number, assembly revision, and maintenance history. Buyers should confirm the exact bearing model and FUJI part number before purchase. Final installation should be completed by qualified maintenance personnel.