A number of things need to be right for a parting job to be successful. There are lots of tutorials online that explain what they are, and the best ways to get your lathe and tooling set up for best possible parting operations. I am pretty sure that everyone here on H-M who does parting has had problems with doing so, I know I have. Study, getting the setups correct, proper feeds and proper speeds for the size of the work, the material, and the rigidity of the machine and setup, sharp cutter with the correct geometry, and more, all come into play to get a successful parting job. The good news is that things get better over time if you study and work at improving the parameters that are important. I suspect we all have issues with parting at times, even when we think we understand it and do a good job of setting it up. I know I do...
A shaky setup with a light machine and flexible tooling and tougher materials will just make things even more difficult.
