Thread chatter only with carbide

[TRA]

Dat's more better.

It's always assumed that when someone has a problem that they have eliminated the most obvious, and that would be the cutting tool. Tool condition and setup are almost always the cause of poor quality work.

Times like these are the reason everyone in the machining business has gone to insert tooling. Tool grinding is a lost art and most shops that resisted went broke paying experienced machinists to stand in front of a grinder instead of a lathe.

I can see why some would want to use HS insert tooling, but you would still pitch it just like carbide, as it will never be right after it's reground, especially a threading tool.

 

[J. Valentine]

That does look much better. Another thing that I experienced is that a barrel can set up harmonics as can any long bar in the headstock if it is only held by the chuck. That's why most make a spider for the open end of the spindle to center the muzzle end. However it also dampens potential harmonics I found . You may already be using a spider so ignore this if you are.
That motot does sound like it is getting very hot. My lathe is also 2 HP single phase but it never seems to get that hot so far that I have noticed.