Mobil Vactra Oil No. 4

Mobil Vactra Oil No. 4 ISO VG 220 Way Oil

Machine Tool Slideway Lubricant for Large Machines, Vertical Ways and High Way Pressures

Mobil Vactra Oil No. 4 is a premium ISO VG 220 machine tool way and slide lubricant designed for precision slideway systems where controlled friction, coolant separability, corrosion protection and lubricant retention are important.

Its higher viscosity makes Vactra No. 4 particularly suitable for large machine tools operating with high way pressures. ExxonMobil also recommends it for vertical and inclined slideways where lubricant drain-down can be a concern and for moderate-service machine tool gear drive mechanisms.

The formulation helps reduce stick-slip and chatter while promoting smooth, uniform slideway movement that supports machining accuracy and surface finish.

Key Features

• ISO VG 220 machine tool way oil
• Designed for precision slideway lubrication
• Recommended for large machines with high way pressures
• Suitable for vertical and inclined slideways
• Helps control lubricant drain-down
• Controlled friction characteristics help reduce stick-slip
• Helps reduce chatter during machine movement
• Compatible with cast iron, steel and non-metallic way materials
• Separates readily from many aqueous metalworking coolants
• Helps limit cross-contamination of coolant systems
• Adhesive properties help retain oil on critical surfaces
• Provides rust and corrosion protection
• Suitable for ball screws, linear guides, headstocks and translating screws
• Suitable for moderate-service machine tool gear drive mechanisms
• Recommended for applications requiring Fives Cincinnati P-50
• Meets DIN 51502 CGLP
• Meets ISO L-GA and ISO L-GB

Designed for Large Machine Tools

Mobil Vactra Oil No. 4 is the highest-viscosity grade in the Mobil Vactra Numbered Series.

ExxonMobil specifically recommends Mobil Vactra Oil No. 3 and No. 4 for larger machine tools where:

• Way pressures are high
• Precision movement is required
• Slideway lubricant retention is important
• Vertical or inclined ways create drain-down concerns

The ISO VG 220 viscosity gives No. 4 greater film thickness and lubricant retention than the lighter Vactra grades.

Use the viscosity grade specified by the machine tool manufacturer.

Vertical and Inclined Slideways

Gravity can cause lubricant to drain away from vertical and inclined machine-tool ways.

Mobil Vactra Oil No. 4 combines relatively high viscosity with adhesive properties that help keep lubricant on critical sliding surfaces.

This makes the product particularly relevant for:

• Vertical slideways
• Inclined slideways
• Large machine tools
• Heavily loaded ways
• Applications where lubricant drain-down is a concern

Stick-Slip and Chatter Control

Machine-tool slideways require controlled friction to move smoothly at both low and normal travel speeds.

Excessive differences between static and dynamic friction can result in stick-slip, where the slide alternates between sticking and moving.

Mobil Vactra Oil No. 4 is formulated with controlled friction characteristics that help reduce stick-slip and chatter.

More uniform slide movement can support:

• Positioning accuracy
• Consistent machining
• Surface finish
• Smooth feed motion

Machine Tool Coolant Separability

Way oil can enter the machine-tool coolant sump during normal operation.

If the oil does not separate efficiently, contamination can affect coolant performance and make tramp-oil removal more difficult.

Mobil Vactra Oil No. 4 is formulated to separate from many water-based and aqueous metalworking coolants.

Effective separation can help:

• Simplify tramp-oil removal
• Reduce coolant contamination
• Support coolant performance
• Support longer coolant sump life
• Reduce cross-contamination between lubrication and coolant systems

Actual separation performance depends on the specific coolant chemistry and operating conditions.

Compatibility With Way Materials

The Mobil Vactra Oil Numbered Series is designed for machine-tool ways constructed from combinations of:

• Cast iron
• Steel
• Non-metallic way materials
• Steel-on-steel surfaces
• Steel-on-polymer surfaces

This allows the product to serve a range of machine-tool slideway designs while maintaining controlled friction characteristics.

Always verify material and lubricant compatibility with the machine tool manufacturer.

Ball Screws, Linear Guides and Other Machine Components

ExxonMobil also identifies the Mobil Vactra Oil Numbered Series for lubrication of:

• Ball screws
• Linear guides
• Headstocks
• Translating screws

Mobil Vactra Oil No. 4 should be selected for these applications only when its ISO VG 220 viscosity is appropriate for the equipment.

Moderate-Service Machine Tool Gear Drives

Mobil Vactra Oil No. 4 is also recommended for moderate-service machine tool gear drive mechanisms.

Its current FZG scuffing performance is listed at:

Fail Load Stage 13 under ISO 14635-1

This laboratory result indicates strong load-carrying performance within the intended machine-tool lubrication applications.

It should not automatically be substituted for a dedicated industrial gear oil where the equipment manufacturer specifies another lubricant type or performance standard.

Fives Cincinnati P-50

The current ExxonMobil product information specifically lists Mobil Vactra Oil No. 4 as:

Recommended for use in applications requiring Fives Cincinnati P-50

The Mobil Vactra grades are aligned differently within the series:

• Mobil Vactra Oil No. 1: P-53
• Mobil Vactra Oil No. 2: P-47
• Mobil Vactra Oil No. 4: P-50

This distinction is important when selecting the correct Vactra viscosity grade for Cincinnati-specified machine tools.

Current Industry Specifications

Meets or exceeds:

• DIN 51502 CGLP
• ISO L-GA, ISO 6743-13
• ISO L-GB, ISO 6743-13

Recommended for use in applications requiring:

• Fives Cincinnati P-50

Application Methods

The Mobil Vactra Oil Numbered Series can be applied through:

• Manual lubrication
• Forced-feed lubricators
• Flood application through circulation systems

The correct delivery method and lubricant quantity depend on the machine-tool lubrication system.

Note: ExxonMobil's specific recommendation for using a Vactra oil as a moderate-duty hydraulic fluid applies to Mobil Vactra Oil No. 1 and No. 2, not No. 4.

Typical Technical Properties

Typical properties represent normal production values and should not be treated as guaranteed batch specifications.

Frequently Asked Questions