Hi I have an Emco style Chinese bench lathe, that I am about to convert to CNC.
I thought that before I started the conversion I would get the machine set up as nicely as possible, so I have made a new toolpost to overcome some of the issues with the standard toolpost, which was pretty rough.
The new toolpost works well, but when I am facing I get a lovely finish on the outer circumference of the work, but as I progress towards the centre the surface starts to tear and gouge. the centre inch or so is aslo deeper than the rest of the surface.
Here's a photo of the best I have been able to achieve.
I am running the 4 jaw chuck at 1500 rpm and 0.0008" per revolution feed rate. I have tried different feeds and slower speeds, but this combination produces the best results so far.
Here are some photos of the toolpost, the lathe and the way piece of steel that I was machining. The steel is 4140, which I know can be tough to machine.
I'd really appreciate some helpful advice.