Hey guys, forgive my ignorance, I do not know much about mini-lathes/mills and know enough about full size to make some parts, but nothing complex yet.
Having said that, I was wondering if anyone here had experience with the Sherline 4000 lathe? Are there any good modifications that can be done to improve it? make it cnc? and what about the attachment that lets you use it as a vertical mill. Any good helps or threads would be great. I searched for a sherline 4000 and didnt really see anything.
Mainly I am looking to use the lathe (and the mill attachment) to do parts that are usually 1" diameter and probably a maximum thickness of 1"

Miniature tools are just like the big ones. The issue is of course power and rigidity. You simply won't be able to do the things you do on a large lathe or mill.

As to the Sherlines I don't own one, nor any of the other small machines. So can't comment on them.

As to CNC'ing a small (micro) machine, generally I would have to say it is a bad idea. At least on the mill. There are many issues there one of which is that the designs are old and thus CNC is an after thought. So the machines are less than Ideal for that. The lathe provides a few more options for CNC conversion but it is still a very small machine and the whole concept is an after thought. An option here is to look at the TIAG (sp) lathe but again I would expect the same issues, but possibly just a bit more flexibility.

For a purely CNC play, the 7" Asian lathes with the flanged spindle are a good choice. A bit of retrofitting may be required and spindle HP will be an issue. The reason I mention this particular lathe is that chucks bolt on as opposed to thread on so you don't have an issue with the chuck spinning off. This can be significant especially if you want to run the spindle in reverse for some CNC operations.

As for threads or sites search the internet there is stuff out there.

My suggestion though would be to pick up a manual machine a learn a bit about how it handles what you want to do. Take this knowledge and apply it to your future CNC machine. Generally though I reccomend that people interested in CNC go to a larger machine than what would handle their manual needs. There are a couple fo reasons for that. One is spindle control, the other is room on the cross slide for tooling. The idea with the cross slide is to be able to mount all the tooling you need for a CNC run.

Dave