Advice on 3 in 1 machines?

I have the same one as you have listed as machine 1.. While it is not perfect it can do an acceptable job if you have the time and the tooling. Perhaps the biggest weak links i find is:

1. all dials are in metric.
2. all lead screws have a good amount of free play.
3. t-slots are 1/2" not the normal 5/8.
4. not a whole lot of movement of the mill table on the y axis
5. mill height not adjustable.
6. Mill spindle is MT instead of R8

Even though it has faults it is usable. I have made spacers for dial bore gauges with the machine as well as re contour combustion chambers for my jet ski engine. the biggest thing with any of these Chinese made machines is you need to check it out and make adjustments to make sure that the centers are in line on the lathe. You will also have to figure out the proper centering of the cutter bits on the tool post to make sure they are centered on the item you are turning.

For the price it is not that bad but if i were to purchase another machine i would get one through http://grizzly.com as they are better quality and they support there equipment better than harbor freight does.

 

R8 has a lot more tooling options over MT IE collet holders and such. with a MT if there is vibrations it can release from the taper where as an R8 is secured with a draw bar.