Everybody has had one time or another few parting off problems, but they are normaly pretty easily solved.
I have been lately looking go new paring off, threading and grooving tools. One friend dropped me a polyvee pulley form tool he brough me a brought me some MGMN 200 inserts and MGEHR shanks to try them.
Worked like a charm, ecept belt on my lathe was slipping....chinese lathe, bad belts and pulleys, stepped up he belt on next step pn pulley. Normal turning was fine, but parting off anything more than 30 mm OD aluminium was a pain. Constant really bad chatter. On 30 mm OD bright steen and on 20 mm tempering steel.
Thought it was the setup we had been earlier playng with. Disassembled the toolpost mount, cleaned all mounting surfaces, tightened the gibs and cleaned the chuck. Hlafan a hout later we cleaned the tool holders, cleaned ad remounted the inserts, tried different toolshanks and inserts and still were getting the chatter.
Hour later chatter we descided to try a lower speed and the chatter was gone. Then we tried faster speed and the chatter was gone
Chatter returned when the "chatter" speed was tried. On close examination it looked like chatter was beltdrive induced....belts and pulleys seem to vibrate a lot at that setting and maybe that excites the vibration?
I have been very tempted some time to modernisize the two stage V-belt drive with a capacitor start small AC motor sytem into two step polyvee belt drive + threaphase motor + VFD.
What do you think?