Novel bio-lubricants were developed for high-speed end milling operation where extreme conditions of contact of the surfaces occurred. The physics involved under specific conditions met in MQCL application during machining operation of steel was investigated. The novelty of this work lies in the successful synthesis of coconut oil in water emulsions containing solid lubricant powders of boric acid and graphite. Characterization was done to get insights into their influence on machining performance during slot cutting operation of steel when applied through minimum quantity cooling lubrication (MQCL). Finally, performance ofthe fluids was assessed in terms of surface roughness, average burr height and chip morphology during slot cutting operation. The best cutting fluid was identified by using Taguchi-gray relational analysis considering two response characteristics simultaneously. Boric acid dissolved emulsion of coconut-oil in water was found to be the best alternative as compared to other fluids especially when applied through MQCL. Its favorable performance was attributed to the combined effect of its low viscosity, low density, low coefficient of friction and high thermal conductivity. The novel solid lubricant-assisted bio-based emulsified cutting fluid through minimum quantity cooling lubrication technique will lead to improved machining performance through cleaner production.