[EMAIL PROTECTED] wrote: > I need to > 1) cut very fine threads on largish diameter tubes. (about 6" diameter > pipe/tubing. Inside and outside thread.). > 2) Cut fine threads on small diameter tubes. (sherline or Taig probably > will do) > > If someone have experience with theis, please advice as to the best > affordable machines for the two tasks. Well, if the Sherline or Taig won't do #1, then it doesn't make sense. Get one machine that will do both (unless you are talking serious production, here.) This is a CNC list, do you need a CNC machine for this, or would a manual lathe with quick change do it? If you need the ability to cut any totally random thread pitch, then CNC starts looking like the answer.
You may need to make custom fixtures (mandrels) to support these thin tubes on the ID while the thread is being cut, expecially the 6" diameter. Outside thread is harder to do, as a circle is easier to push in than out, but you may need support on either operation. A 6-jaw chuck can be helpful in holding thin tubes, but you may need better support than that provides. Definitely get a chuck with 2-part jaws, as machinable soft jaws might be made to grip your parts well without needing the mandrels. You can make "wide jaws" that close like a collet and support the piece around 330 degrees of the circumference, but if you never do the same diameter twice, that may not be the best solution. If you do the same diameter very often, that's the way to go. Also, get an "adjustable chuck", it has bolts that allow the chuck body to be moved slightly so it will grip a particular size very accurately on-center. As for CNC machines, unless you have a high budget, you probably will need to make your own. You could buy a 12" import lathe and convert, buy a used lathe and convert, buy a retired CNC lathe and install EMC2 and necessary control hardware (PC, motor drives, may need to replace motors, etc.) The advantage of the used CNC machine is it will already have ballscrews and the motor attachments, but may need repair work. Maybe you need to tell us more about the level of investment (both money and time) you have to put into this, and what amount of work you need to have it do (a couple pieces a day, or 200 a day, etc.) and we can be more specific. Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
