Selecting the right fluid, for the right job can be complex with so many operating variables for metalworking professionals to consider. This advanced product selector tool allows you to evaluate lubricant choices in-line with your application needs.

Based on laboratory testing* and end-user observations**, mineral, synthetic and plant-based products have been rated for their performance, value and safety attributes.

Determine your priorities, then receive recommendations that help to balance your cutting and cooling requirements with worker safety and whole life lubricant costs. The ‘winning lubricant’ will support you in cutting the compromise on the factory floor: giving you a natural advantage.


High performance products must offer long fluid life and retained lubricity to support precision machining and enhanced productivity. Mineral oils have dominated the market, despite the challenges sometimes associated, with smoke generation, because previous plant-based technologies have failed to meet these performance criteria. The trade-off has been increased fire risk and compromised working conditions. Could plant-based alternatives now deliver comparable oxidation stability, while reducing the problems that are traditionally associated with plant-based fluids.

Is improving productivity important to you?

Mineral oils have generally prevailed over plant-based alternatives because of their long life properties. Overcoming the oxidation stability challenge has always been key to harnessing comparable performance benefits in biolubes. Our laboratory tests* confirm this mission has been met by Castrol’s latest generation of plant-based fluids.

Is achieving better quality outputs a priority?

Entrained air can make coolants less effective. Testing lubricants to see how quickly air bubbles disperse gives an important indication of performance. Castrol’s high viscosity plant-based fluids released air much faster than competitive products of a similar chemistry.*


Best value lubricants should be considered in terms of total cost of ownership, not lowest unit price. Factors such as frequency of oil changeover, tool life, lubricant waste, factory maintenance and consistency of work piece all have an impact. Reducing that impact means working with lubricants that promote uptime and support longer-term savings. For many, mineral-based fluids have been the only answer. But at what hidden cost to the wider operation?

Is reducing consumption of metalworking fluids important to you?

Volatility and drag out are the principal contributions to lubricant consumption. Lubricants that evaporate less offer better value. The more oil that vapourizes; the more fluid consumption increases. Though there is a tendency to overlook this as a cost consideration, factoring evaporation into procurement decisions could deliver savings over time.

Is lowering your maintenance requirements important to you?

Extending time between oil changeovers is an important maintenance and cost consideration. Though premature oil breakdown has been a major barrier for plant-based products, comparable oxidation stability* to mineral oils can now be demonstrated.


Worker safety concerns associated with oil mist and smoke have always been an industry challenge. From a fire risk and employee wellbeing perspective, lubricant choices can have important consequences on the factory floor. Though the priority placed on these concerns varies from region to region, the world’s metalworking professionals often have to accept these compromises in pursuit of high performance. Reducing these downsides has been the focus of ongoing research and development.

Is improving fire safety important to you?

For all their performance merits, mineral oils breakdown much sooner than natural or natural-based products and present a higher fire risk. Biolube make-ups have inherently higher flash points, minimising air pollution and flammability problems.

Is improving worker safety important to you?

Polluted air can have adverse effects on employee wellbeing, with misty environments creating unpleasant working conditions and slip hazards. Plant-based fluids tend to smoke less and don’t release as much mist** as traditional mineral oils, making for a safer and more productive working environment.

Get your results

Note: The data and information given is believed to be accurate according to the test conducted. However, no warranty or representation, express or implied, is made as to its accuracy or completeness. Data provided is based on standard industry methodology under laboratory conditions and is given as a guide only.

* Performance Bio NC cutting fluids were tested using standard industry methodology to assess the oxidation stability, flash point, ability to separate entrained air, tapping torque, evaporation rate and friction properties of each grade in the range against existing Castrol and competitive mineral and plant-based fluids of a similar grade and viscosity.

** Based on Castrol experience