- Joined
- Nov 16, 2012
- Messages
- 5,596
I am using carbide, CCMT / CCGT in this instance. The diameter is larger, away from the headstock. I did not know about the need for a cut to stabilize.
Yes, depending on the insert type, angle setting, speeds/feeds etc, when the cutter hits the metal, it can either push the cutter away or cause it to dig in at first. I think you're in safe territory and need to learn and explore the machine. Are you measuring the piece with a micrometer or calipers?
What are you speeds/feeds and DoC? Is it 4140 annealed, pre-hard or rusty HR? Are you getting a shiny finish or a matte/fuzzy finish? All these things are factors and/or tell-tale signs of what is happening with the cut. But anyhow, my lathe is known and trusted and I would not lose sleep over 3 tenths on a 1" cut. If it was a 3" long cut on a 3" dia piece of clean/annealed bar-stock with a light DoC at proper F/S and it was getting 3 tenths per inch on a steady taper then, I'd dig-in and fix it.
Ray