Originally Posted by
DSpeck
Unless you are really looking for the challenge of building your own spindle (I can respect that!), you may be well ahead for your build to buy an older Hardinge small lathe (a DV-59 variant, for example), and build that into your system. They have wonderfully accurate spindles, and come with 5C collet capability built in. Usually they have a manual collet closer, as you mentioned above. You will see many of these lathes in the $1000-$2000 range, especially on ebay or Kijiji. I would expect that you would end up paying at least that in building your own spindle. Since you will be making it into a CNC lathe anyway, you won't need one that comes with lots of accessories, which can definitely lower the cost to buy.
If you want to add a chuck, these lathes have either a 4 degree Hardinge spindle nose, or a threaded 2-3/8"-10 spindle nose. The 4 degree taper nose is the better choice if you want to do much with reverse in your work - it won't unscrew and fall off if you reverse too fast.
HTH.