I had a quick look tonight at runout, from what i can measure there is no runout in the spindle socket (ER20) so thats ok, but the collet - thats another story!


I put the 2mm tool in with about 20mm shank protruding, near the collet there was 0.1mm runout - pretty bad, further down the shank near the flutes it measured 0.1mm again. I marked the retaining nut and spindle at the point with the largest reading and rotated the collet in the socket 180deg.


The nut was tightened back to the same point and the measurements taken again. This time the high point had moved with the collet but was the same.

Sounds like a totally junk collet :)
Will find some decent ones i think.

This is the cut spec leaflet, the single-flute E5E47 range.

Click image for larger version.  Name: YG-1 Alu-Power Carbide End Mills.pdf  Views: 573  Size: 3.18 MB  ID: 19480

The material is firmly clamped, no movement, either 3mm or 5mm thick.