Chuck master pinion

[Okapi]

I'm a convinced user of 4 jaws chucks, two are with 4 independent jaw, one is mounted with a W20 support, the second normally on the nose and have only an old 3 jaws used for cutting bolts etc…
But for making some repetitive work like cams on stems, I prefer to use a steel precision pierced bush drilled with the eccentricity I need on the result, a cut is made on the thinnest side and with a 4 jaws it gives a perfect result, after some time we have a lot of bushes covering current needs and with a precision of 2/100millimeter easily obtained.