Re: cnc lathe project

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Denis" <fprckq@...> wrote:

>
> Hello all,
> I want to build a small cnc lathe with a 6 jaw chuck so I can work plastics.
> From what I've seen lathe chucks have 4 joint types, cam lock, threaded nut and taper, screw on chuck ( like south bend ) and some imported chucks that bolt on the back.

Another option besides a 6 jaw chuck is to put a set of full jaws on a 3 jaw chuck. Full jaws or pie-jaws are aluminum jaws with mount machining to match the 3 jaw chuck jaw mount. They are almost 1/3 the size of the chuck face, with a small clearance between the jaws. These jaws are bored ( by you) to a size and depth that permit strong workholding with the least surface deformation. They will perform much the same as a 6 jaw, but with much less surface deformation of the part. These are available to match most popular manual, air or hydraulic chucks. See US Shop tools for a good selection. A set of 3 for a 6 inch chuck starts around $70 for a 2" length

5C collets can also be adapted with these kind of machinable jaws. 5c-collets are available that can hold parts up to 4-6 inches in diameter.

From a quick google search:
http://www.jtsmach.com/jtswebshop/Workholding/ch049.asp

For best stability I would recommend getting a step collet closer ( pot chuck) with the 5C, rather than a standard collet closer system. These screw onto the threads that you will see on many 5C spindle noses. 5C indexer sometimes have the threaded option as well.

Fred Smith - IMService
http://www.imsrv.com