I restored a Bridgeport Boss last spring that came equipped with an Erickson 30 (NMTB) spindle that was in fairly rough shape. Having a set of ER-40 collets in my poseesion, I plan to use them as my primary tool holders and leave the collet chuck in the spindle. I put a brand new ETM ER-40 collet chuck on the machine tonight and was able to get runout on the outside of the tool holder to roughly .0005". With a 1/2" drill rod chucked in a collet and the dial indicator set about an inch below the collet face, I get a little less than .001" runout. Is this acceptable for general CNC machining?
-Steven Balder