Custom R168 Inch Deep Groove Ball Bearing (1/4″ × 3/8″ × 1/8″)

R168 Inch Deep Groove Ball Bearing Overview

The R168 bearing is a miniature inch-series deep groove ball bearing with a 1/4 in bore, 3/8 in outside diameter, and 1/8 in width (6.35 × 9.525 × 3.175 mm). JN Bearings supplies custom R168 variants for OEM and bulk buyers who need fractional dimensions, defined load ratings, and configurable seals, materials, and lubrication for RC models, medical instruments, and compact industrial drives.

These parts belong to the broader miniature precision bearings family and share the same deep raceway geometry as standard deep groove ball bearings, but in an imperial R-series footprint for tight layouts.

R168 Bearing Dimensions and Specifications

Standard inch-series R168 dimensions follow published miniature bearing catalogs. Use this table for fit checks before specifying seals, clearance, or material upgrades.

Parameter	Inch	Metric
Bore diameter (d)	0.2500 in (1/4 in)	6.350 mm
Outside diameter (D)	0.3750 in (3/8 in)	9.525 mm
Width (B)	0.1250 in (1/8 in)	3.175 mm
Chamfer radius (r min.)	—	0.1 mm (typ.)

Custom Modifications Available

• Materials: Chrome steel (52100), stainless steel, or hybrid ceramic (steel rings + ceramic balls) for corrosion resistance, higher speed, or electrical isolation.
• Cages: Nylon (polyamide), ribbon steel, or brass—selected for noise, speed, and temperature.
• Closures: Open, metal shield (ZZ), or rubber seal (2RS) configurations.
• Lubrication: Standard grease, high-temperature grease, low-temperature oil, or food-grade grease for cleanroom or medical use.
• Precision: ABEC-1 through ABEC-5 (or equivalent) grades and custom radial clearance upon request.

Load Ratings and Speed Limits

R168 bearings handle combined radial loads and light bidirectional axial loads typical of small rotating shafts. Catalog values below are typical for standard chrome-steel R168 open or shielded designs; confirm final ratings on your order confirmation for your exact seal, material, and clearance.

• Dynamic load rating (C_r): 460 N (typ.)
• Static load rating (C_0r): 173 N (typ.)
• Limiting speed (grease lubrication): 48,000 rpm (typ.)
• Limiting speed (oil lubrication): 56,000 rpm (typ.)

Deep raceway grooves and matched rolling elements keep friction low at high RPM, but actual service speed depends on alignment, lubrication, seal drag, and operating temperature.

Material Options for R168 Bearings

• Chrome steel: Default for motors, RC drives, and automation spindles where hardness and load capacity matter most.
• Stainless steel: For washdown, humidity, or mild chemical exposure where rust prevention is critical.
• Hybrid ceramic: Ceramic balls reduce weight and heat at very high speeds; useful in medical handpieces and precision spindles.

Cage material is matched to speed and temperature: nylon for quiet high-speed runs, brass for elevated heat, and steel ribbon for general industrial duty.

Applications for R168 Inch Ball Bearings

The compact R168 footprint fits shafts and pulleys that cannot accept larger metric miniature bearings.

Application	Key requirement	Typical R168 build
RC cars and drones	Low weight, high RPM	Chrome steel, R168 ZZ shielded
Medical and optical instruments	Low noise, clean operation	Stainless or hybrid, ABEC-5, food-grade grease
Small electric motors	Efficiency, long life	Chrome steel, open or ZZ, standard grease
Robotics and 3D printers	Low torque, repeatable motion	Stainless 2RS in dusty environments

Seal and Shield Options (ZZ vs 2RS vs Open)

Closure	Code	Best for	Friction	Contamination protection
Metal shield	ZZ	High-speed RC and motor shafts	Very low	Moderate (dust)
Rubber seal	2RS	Damp or dusty industrial settings	Medium	High (dust and moisture)
Open	Open	Oil-bath or externally sealed housings	Lowest	None (housing must protect)

When Not to Use R168 Bearings

R168 is not the right choice for every rotary problem. Consider these limits before ordering:

• Heavy single-direction axial loads: Use angular contact ball bearings or thrust bearings when axial force dominates.
• Very large radial loads on a small shaft: A larger inch or metric deep groove size may be required.
• Unsealed open bearings in dirty environments: Specify ZZ or 2RS, or protect the housing.
• Extreme temperature without special grease/clearance: Request high-temperature lubrication and heat-stabilized clearance.

For a broader comparison of bearing types and selection logic, see our guide on the advantages of deep groove ball bearings (installation and maintenance details are covered there—not duplicated on this SKU page).

OEM, Bulk Supply, and Lead Time

JN Bearings supports B2B programs through our OEM/ODM services:

• Order volumes: Sample and prototype quantities; 100–999 pcs; 1,000–4,999 pcs; and 5,000+ pcs OEM/wholesale batches.
• Quotation response: Engineering review and pricing typically within 24 hours on business days.
• Customization: Laser marking, custom packaging, preset grease, clearance codes, and inspection reports on request.
• Compliance: Production under documented quality systems; see certifications for ISO 9001 and related compliance statements.

Share bore/shaft loads, speed, temperature, and environment when requesting a quote so we can confirm R168 versus an alternate series before production.

R168 Selection Guide: Cage and Environment

Cage material	Speed	Temperature	Typical use
Nylon (polyamide)	High	Moderate	Quiet medical tools, RC models
Ribbon steel	Standard	High	General motors and automation
Brass	Moderate	Very high	Hot or heavy-duty environments

Frequently Asked Questions About R168 Bearings

What is the exact size of an R168 inch ball bearing?

Bore 1/4 in (6.35 mm), outside diameter 3/8 in (9.525 mm), and width 1/8 in (3.175 mm). These are standard R-series inch miniature dimensions used across North American equipment drawings.

What is the MOQ for custom R168 bearings?

We accept sample and prototype orders for validation, then scale to 100–999 pcs, 1,000–4,999 pcs, or 5,000+ pcs OEM batches. MOQ depends on material, seal type, and customization; state your target volume on the quote form.

What is the typical lead time?

Standard chrome-steel R168 builds often ship faster than fully custom stainless, hybrid, or special-clearance lots. We confirm lead time with your quotation based on current production load and inspection requirements.

Can I get food-grade grease in R168 bearings?

Yes. Specify food-grade or cleanroom-compatible grease, high-temperature synthetic oil, or dry lubricant when you submit requirements. We pack lubrication to match your audit and operating temperature range.

How do R168 ZZ shielded bearings compare to 2RS sealed types?

ZZ (metal shield): Non-contact shields, lowest friction, best for high RPM, limited dust protection.
2RS (rubber seal): Contact seals, better dust and moisture sealing, slightly higher drag. Choose based on contamination level versus speed.

How long will an R168 bearing last?

Service life depends on load, speed, alignment, lubrication, and contamination—not on catalog size alone. Matching seal type, clearance, and grease to the application typically delivers longer life than off-the-shelf parts used outside their design window.

Specifications and References

• Dimensions and load ratings cross-checked against published inch miniature bearing catalogs for R168 / R168B class parts (typical values noted above).
• General bearing terminology and load concepts: Ball bearing (Wikipedia).
• Geometric and rating context: ISO 15 (rolling bearing boundary dimensions) and ISO 281 (dynamic load ratings)—applied at quotation for your exact build.

Request a quote: Send shaft dimensions, load/speed targets, environment, and target volume via our contact page for an R168 engineering review and pricing.