I am trying to do OD threading on SS316L annealed pipe. wheni was threading on SS316L non annealed pipe everything was good. but after i bought material with annealing things get worst. the chips get stuck on the insert tip and because of that i cannot have consistency in the threads depth. i have tried G92 and G76 cycles both. cannot get rid of chattering . if i reduce the rpm to 500 the chip sticks to the insert and there is variation on threads depth. if i increase the speed to 1000 or 1300 there is chattering . i am using VM7 grade vardex insert ER14tpi. threading is to be done 16mm npt on 1 side and 16mm on the other followed by NPS thread totallong 58mm. Please help friends.