The NATIONAL Oil Seal 1.688x2.725x0.547 M/L LEATHER is designed for rotary shaft applications requiring lubricant retention around a 1.688-inch shaft within a 2.725-inch housing bore.

This seal uses an industrial leather sealing element supported by a metal case or structural carrier. Leather oil seals have historically been used in heavy machinery, agricultural equipment, gearboxes, transmissions, and older industrial systems because the material can conform well to the shaft surface when properly lubricated.

The M/L profile is manufacturer-specific. The exact leather-lip geometry, metal support arrangement, lip orientation, outside-case construction, and installation direction should be verified against the original NATIONAL seal, technical drawing, or equipment specification.

Unlike many modern elastomer seals, a leather seal should generally not be operated dry. Adequate lubrication at the sealing interface is important to reduce friction, heat generation, hardening, and premature wear.

Typical compatible lubricant/service environments include:

• Mineral oils
• Gear oils
• Bearing oils
• Bearing grease
• Petroleum-based lubricants
• General industrial lubricated shaft service

Leather sealing performance depends strongly on leather grade, lubricant type, shaft speed, surface finish, temperature, and operating environment.

The inch dimensions convert approximately to:

Shaft diameter: 1.688 inches or approximately 42.88 mm

Housing diameter: 2.725 inches or approximately 69.22 mm

Seal width: 0.547 inch or approximately 13.89 mm

The 1.688 × 2.725 × 0.547-inch configuration is suitable for medium-size bearing housings, gearboxes, transmissions, agricultural equipment, industrial drives, and legacy machinery originally designed for a leather-type shaft seal.

⚙️ Applications

• Industrial gearboxes
• Bearing housings
• Mechanical transmissions
• Agricultural machinery
• Construction equipment
• Conveyor drive assemblies
• Industrial shaft assemblies
• Older mechanical equipment
• Legacy rotating machinery
• OEM restoration applications

🎯 Benefits

✔ Genuine industrial leather sealing element

✔ Suitable for lubricated rotary shaft applications

✔ Can conform to minor shaft-surface irregularities

✔ Suitable for 1.688-inch shaft assemblies

✔ Metal-supported M/L construction

✔ Well suited to maintenance of legacy machinery

✔ Suitable for slow-to-moderate shaft speeds when properly lubricated

✔ Useful for overhaul and restoration work

✔ Replacement ready when dimensions and M/L construction match

🧠 Technical Insight

• NATIONAL M/L Leather Seal Reference
• Inch-Size Rotary Shaft Seal
• Oil-Treated Industrial Leather
• Metal-Supported Seal Construction
• Lubrication Is Essential
• Suitable for Slow-to-Moderate Speeds
• Approximately 42.88 mm Shaft Diameter
• Exact M/L Cross-Section Must Be Verified

✅ Key Features

• NATIONAL Industrial Seal
• M/L Profile Reference
• Genuine Leather Sealing Element
• Metal-Supported Construction
• Inch-Size Dimensions
• 1.688x2.725x0.547 Configuration
• Legacy Equipment Replacement
• Cross-Reference Support Available

📊 Specifications

Brand: NATIONAL

Model / Profile: M/L

Size: 1.688 × 2.725 × 0.547 inch

Metric Equivalent: Approximately 42.88 × 69.22 × 13.89 mm

Type: Industrial Leather Rotary Shaft Oil Seal

Material: Genuine Oil-Treated Industrial Leather

Profile: M/L

Construction: Manufacturer-Specific Metal-Supported Leather Shaft-Seal Construction

Lip Design: Leather sealing lip; verify exact M/L lip geometry and orientation against the original seal or technical drawing

Dust Lip: Not assumed; verify from the actual M/L construction

Spring Type: No spring unless the original seal specifically indicates one

Shaft Diameter (ID): 1.688 inches / approximately 42.88 mm

Housing Diameter (OD): 2.725 inches / approximately 69.22 mm

Width: 0.547 inch / approximately 13.89 mm

Pressure Capability: Primarily low-pressure rotary shaft-sealing service unless otherwise specified

Lubrication: Oil or grease lubrication is generally required; leather should not normally operate dry

Temperature Range: Depends on leather grade, lubricant, shaft speed, and actual operating conditions; verify application-specific limits

Speed Consideration: Generally best suited to slow-to-moderate shaft speeds with adequate lubrication

Installation Consideration: Confirm shaft finish, housing-bore condition, lip orientation, installation depth, and pre-lubricate the leather sealing surface before startup where appropriate

Application Class: Industrial Bearing, Gearbox, Transmission, and Legacy Rotating Equipment

Standard: Inch-Size Specialized Leather Shaft Seal

🔁 Equivalent

Suitable replacement or cross-reference candidate for compatible:

• NATIONAL M/L Leather Shaft Seal
• NATIONAL 1.688x2.725x0.547 Oil Seal
• 42.88x69.22x13.89 Leather Seal
• 1.688-Inch Shaft Leather Oil Seal
• Metal-Supported Leather Shaft Seal
• Industrial Leather Bearing Seal
• Gearbox Leather Oil Seal
• Transmission Leather Shaft Seal
• Legacy Equipment Oil Seal
• OEM M/L Leather Seal

The same dimensions alone do not guarantee interchangeability. The replacement must match the original M/L cross-section, leather-lip geometry, lip orientation, metal support arrangement, outside-case construction, installation direction, leather grade, lubricant requirements, and operating conditions.

(Always verify dimensions, M/L construction, leather-lip orientation, shaft finish, housing condition, installation depth, lubricant compatibility, shaft speed, temperature, runout, and operating conditions before ordering.)

📦 Availability

✅ In Stock

🚚 Fast Delivery Available

🌎 Worldwide Shipping Available

📦 MOQ: 1 Piece

🏭 Suitable for gearbox overhaul, bearing-housing maintenance, transmission repair, agricultural-machinery servicing, construction-equipment maintenance, conveyor-drive repair, legacy-equipment restoration, and compatible OEM replacement applications.

📲 Contact via LINE ID: dusitrea

📧 Email: sales@seal4go.com

💬 Technical support available before ordering

🔍 Assistance available for cross-reference and equivalent part identification