Abstract:The reproducibility of a reaming test was analysed to document its applicability as a performance test for cutting fluids. Reaming tests were carried out on a drilling machine using HSS reamers. Workpiece material was an austenitic stainless steel, machined using 4.75 m·min -1 cutting speed and 0.3 mm·rev -1 feed. A mineral straight oil and a water-based lubricant at two different oil concentrations were compared with respect to hole quality, evaluated in terms of surface finish (conventional arithmetic mean roughness Ra and roughness profiles), and hole geometry (hole diameter and roundness). Process reproducibility was assessed as the ability of different operators to ensure a consistent rating of individual lubricants. Absolute average values as well as experimental standard deviations of the evaluation parameters were calculated, and uncertainty budgeting was performed. Results document a built-up edge occurrence hindering a robust evaluation of cutting fluid performance, if the data evaluation is based on surface finish only. Measurements of hole geometry provide documentation to recognise systematic error distorting the performance test.[ He is an internationally recognised expert in manufacturing and metrology, having published over 200 technical papers in international journals and conference proceedings. His theoretical models quantifying the role of friction and lubrication in metal cutting are described in textbooks worldwide. He has been the Supervisor of more than 100 MSc students and over 20 PhD students. He has been initiator and coordinator of major framework programmes, and created and directed since its formation the Centre for Geometrical Metrology (CGM). Moreover, he has established a transnational virtual institute for geometrical metrology between DTU and Padova University. He is a Fellow of the International Academy for Production Engineering (CIRP) and panel member of the Foundation Committee of the European Society for Precision Engineering and Nanotechnologies (Euspen).