Ganesh GT3880 lathe cutting API NC44 pin connection on 1018 HR at 200 rpm's averaging 200 sfm from end to end. Brand new Stellram toolholder with new 22ER4API382 carbide insert. Using Rigid thread cutting oil instead of coolant. Machine is level and all pads are tight. All mounting bolts are tight along with all chuck bolts both for jaws and mounting. Depth of cut starts at .020" and minimizes to .003" with the final finish pass at .0015". Taper angle is 2.0" per foot and pitch is .250". Insert is a topper style lay-down thread graded at SP4066. Severe chatter as cuts progress to depth. Full depth is .1218". Insert cutting within parameters of both insert capabilities and material cut ability. We have done all we can to alleviate this problem short of slowing the part down. Part will exhibit slight chatter even at 70 rpm. Unacceptable as far as customers are concerned and ourselves as well. This does not meet our ISO9001 standard for finished parts.
