Product Description
The 688 is a miniature deep groove ball bearing designed for precision rotary and automation applications. Available in multiple variants—open, shielded (ZZ), and double-sealed (2RS)—it features. Manufactured from 52100 chrome steel for durability and reliability in industrial environments, with optional stainless steel variants for corrosive settings. The bearing is cross-referenced across multiple manufacturer standards and offers excellent load performance suitable for demanding applications. Select the seal type based on your environment: open bearings for clean conditions, sealed variants for moisture and contamination protection.
Specifications
Material
| Ring Material | 52100 Chrome Steel |
| Ball Material | 52100 Chrome Steel |
| Cage Material | 300 series stainless steel (some variants) |
| Material Variants | Stainless steel (INOX) available |
Performance Ratings
| Precision Class | ABEC 1/3, Grade 0/6 (select manufacturer/variant) |
Seal/Shield Options
| Seal Shield Options | Open, double shielded (ZZ), double rubber sealed (2RS), stainless sealed (ZZ/W6-INOX) |
Part Numbers
| Primary Part Number | 688 |
| Cross-Reference Numbers | 688ZZ, B688ZZ, 688-2RS, MR688-2RS |
| Beari |
Frequently Asked Questions
Q: What are the dimensions of bearing 688?
A: Bearing 688 is a miniature deep groove ball bearing. Open, shielded (ZZ), and double-sealed (2RS) variants are available.
Q: What cross-reference part numbers match bearing 688?
A: Bearing 688 cross-references to 688ZZ, B688ZZ, 688-2RS, MR688-2RS, and stainless steel (INOX) variants. Confirm exact seal type and material grade required for your application before ordering, as shielding and sealing options affect performance in wet or contaminated environments.
Q: What is the load rating for bearing 688?
A: Bearing 688 dynamic load ratings vary depending on seal variant. The open bearing supports higher loads, while sealed variants (ZZ, 2RS) sacrifice some load capacity in exchange for contamination protection. Select the variant matching your application loads.
Q: What materials are used in bearing 688?
A: Bearing 688 inner and outer rings are manufactured from 52100 chrome steel with possible stainless steel (INOX) variants available. Balls are 52100 chrome steel, and cage material is typically 300 series stainless steel in some variants. Chrome steel bearings suit general industrial use; stainless variants are required for corrosive or wet environments.
Q: What precision class does bearing 688 meet?
A: Bearing 688 is available in ABEC precision classes suitable for rotary and automation applications. ABEC-1 and ABEC-3 are standard for general use, while ABEC-5 or higher are required for precision machinery. Verify your equipment precision requirements before selecting a bearing variant.
Q: Should I use bearing 688 open, shielded (ZZ), or sealed (2RS)?
A: Choose open bearings for clean, dry applications with maximum load capacity. Use ZZ shielded bearings for light contamination protection. Double-sealed (2RS) bearings are required for wet environments, dusty conditions, or cold storage. Sealed options reduce load capacity but extend bearing life in harsh conditions.
Q: How do I store bearing 688?
A: Store bearing 688 in a clean, dry environment at room temperature (15–25°C). Keep bearings in original packaging or sealed containers to prevent moisture and dust contamination. Avoid extreme temperature fluctuations, direct sunlight, and storage near chemicals or corrosive materials. For long-term storage, periodically inspect for corrosion, especially sealed variants.
Q: What equipment uses bearing 688?
A: Bearing 688 is commonly used in electric and manual pallet jacks, lift trucks, conveyors, automation machinery, rotary equipment, and precision instruments. Verify compatibility with your specific equipment before installation. The bearing is suitable for industrial and warehouse material handling applications.
