SG04 and SG08 are ultra-miniature guide roller bearings engineered for compact linear guide rail systems. Their design fully embraces miniaturization: an exceptionally small envelope and low mass combined with precisely machined rolling elements and raceways that deliver smooth operation, accurate positioning, and quiet running at high rotational speeds. These bearings provide stable, reliable support in demanding applications where installation space is strictly limited.
What Are Ultra-Miniature Guide Roller Bearings?
Guide roller bearings (also called track roller bearings or cam followers) support and guide rolling motion along a track or guide rail. They typically feature a thick-walled outer ring that can accommodate high radial loads and resist shock, and a rolling-element set that minimizes friction between the moving carriage and the stationary rail. Ultra-miniature guide roller bearings shrink this architecture to an extremely small outside diameter, enabling precise guided motion where a standard miniature bearing would not physically fit. The SG04 and SG08 series are designed for exactly these space-constrained, precision-driven applications.
Key Features of SG04 and SG08
- Ultra-compact envelope — optimized for installations where axial and radial space is strictly limited, such as compact linear guide rails in precision instruments.
- Light weight — the miniaturized design reduces rotating mass, which is valuable for high-acceleration moving stages and sensitive mechanisms.
- High-precision geometry — rolling elements and raceways are precisely machined to deliver smooth, low-friction running and accurate positioning at high rotational speeds.
- Stable support under demanding conditions — the ring and rolling-element set work together to provide reliable, repeatable guidance in precision machinery.
- Quiet, smooth operation — suitable for high-tech equipment where low noise and low vibration are required.
Technical Specifications Overview
The SG04 and SG08 series cover the smallest end of the guide roller bearing range. As ultra-miniature parts, exact dimensions (bore, outer diameter, width) and load/speed ratings are model-specific and depend on the seal, clearance, and cage options selected. Please request the official dimension and rating data sheet from our engineering team for the specific part number you require, so every value can be confirmed for your application. We will never publish unverified ratings — contact NLHB for the certified parameters of SG04 and SG08.
Selection Guide: Choosing the Right Miniature Guide Roller
Selecting the correct guide roller bearing for a compact linear guide rail involves several practical considerations:
- Required envelope. Confirm the available bore, outer diameter, and width envelope in your assembly before selecting between SG04 and SG08.
- Radial and axial loads. Compare the application loads against the bearing’s rated dynamic and static load capacity. Request the certified rating for the specific part.
- Speed. For high-speed stages, confirm the limiting speed and lubrication type (grease or oil) for the chosen part.
- Clearance and tolerance. Specify the internal clearance (e.g. C2/C3/C4) and tolerance class appropriate for your precision requirement.
- Sealing and lubrication. Decide between open, shielded, or sealed versions based on contamination, maintenance access, and relubrication needs.
- Operating environment. Consider temperature, humidity, and any corrosive media when specifying materials, seals, and lubricants.
When in doubt, share your rail type, moving mass, and duty cycle with our engineers — we will recommend the exact SG04 or SG08 configuration that fits.
Typical Applications
Because of their compact size, low weight, and precise running, SG04 and SG08 ultra-miniature guide roller bearings are used wherever space is tight but motion must be accurate and repeatable:
- Precision instruments — optical, metrology, and laboratory equipment with compact guided stages.
- Miniature and micro machinery — small actuators, micro-positioners, and desktop automation.
- High-tech equipment — semiconductor handling, electronics assembly, and medical device stages that demand quiet, precise linear motion.
- Compact linear guide rails — the primary intended use, where the roller’s small outer diameter keeps the overall guide assembly slim while providing stable, reliable support.
Cross-Reference & Interchangeability
Guide roller bearings of this miniature size class are commonly available from major manufacturers under their track roller / cam follower / support roller programs (for example, the track roller ranges of SKF, INA/FAG, NSK, NTN, and Timken). Because the SG04 and SG08 part designations are NLHB’s own model identifiers, a direct like-for-like interchange to a specific SKF, NSK, NTN, FAG, INA, or Timken part number must be verified against the certified dimension sheet (bore, outer diameter, width, stud style, and seal configuration). Please provide the required dimensions and we will confirm the exact cross-reference — do not assume a brand interchange from the model name alone. We can match SG04 / SG08 to the equivalent track roller in each brand’s catalog once the parameters are confirmed.
Installation & Maintenance
- Cleanliness. Keep bearings and mating track surfaces clean during installation; miniature bearings are sensitive to contamination.
- Correct mounting force. Apply mounting force only to the ring being fitted — never strike through the rolling elements, which can brinell the raceways.
- Alignment. Align the roller axis square to the guide rail to avoid edge loading and premature wear.
- Lubrication. Follow the recommended grease or oil fill; for sealed versions, do not over-lubricate, as excess grease increases running temperature.
- Periodic inspection. Listen for noise and check for play; replace rollers in matched sets on a guide rail to preserve running accuracy.
Frequently Asked Questions
Q: What is the difference between SG04 and SG08?
A: SG04 and SG08 are different ultra-miniature sizes within the same guide roller bearing family, each offering a different envelope and load capacity. The correct choice depends on the available installation space and the load/speed requirement of your guide rail. Request the dimension sheets for both to compare.
Q: Can SG04 and SG08 bearings run at high speed?
A: Yes. Their rolling elements and raceways are precisely machined for smooth running, but the actual limiting speed depends on the specific dimensions, lubrication, cage, and seal option. Confirm the certified speed rating for your exact part.
Q: Do you provide cross-reference to SKF, NSK, NTN, FAG, INA, or Timken?
A: We can supply a verified interchange once the required dimensions and configuration are confirmed. Because SG04 / SG08 are NLHB model identifiers, please provide the bore, outer diameter, and width so we can match the exact equivalent.
Q: Are these suitable for cleanroom or precision instrument use?
A: Yes. Their compact size, low friction, and quiet, smooth running make them well suited to precision instruments and high-tech equipment. For cleanroom service, specify the sealed version and compatible lubricant.
Ningbo ShuangHua Bearings Co., Ltd (NLHB) — manufacturer of miniature and ultra-miniature guide roller bearings. Contact our engineering team for the certified dimension, load, and speed data of SG04 and SG08, or for a verified brand cross-reference.