Hi there,
I have set my Micro Mill up for grinding with a high speed rotary tool (approximately 30000 RPM) to grind internal shapes under CNC control, but I'm having trouble.
I am trying to grind cast iron with a grinding wheel that is 15.2mm in diameter. I have the wheel going at full speed, taking small 'cuts' (or whatever they're called) without any coolant. The problem is that the finish is less than perfect (much less!!!). It is leaving grooves behind and if you run your finger nail perpendicular to the direction of the 'cut' it feels rough.
I'm not sure if the wheel I'm using is classed as coarse or fine, but it doesn't seem very coarse. I also dressed the wheel on a diamond before use to make sure that it was parallel.
I'm using a feedrate of between 1 and 4 IPM, but there is little difference between the finishes. Does anyone have any suggestions as to what I can try to get a smooth, 'proper ground' finish? It almost needs to be like glass.
Thanks
Warren