Here is what I did with my lathe spindle: http://www.wallacecompany.com/cnc_lathe/HNC/
See picture 11 and 18. Picture eleven is what I am currently using. Picture eighteen shows the timing belt a little better. The gearing ratio is 1:1. The encoder is a one inch U. S. Digital disk with 1250 counts or 5000 pulses per revolution. After solving an EMI problem, it is now working well. You may not need the the higher resolution, but the more the better until you max-out your encoder input at the maximum spindle speed. I believe at 3000 RPM both my spindle and encoder input are at their limits. Some day, I would like to come up with a direct drive system with a three inch encoder disk mounted to the spindle shaft. The U. S. Digital website indicates that they can do custom disks, but I have no idea what the cost would be. I would also like to be able to make my own glass disks. Maybe using an aluminum sputtering coating like the amateur telescope makers use for mirrors and either laser etch or photo-etch the grating (proper word for tiny lines?). It would be nice to be able to do some milling operations with the lathe, requiring a spindle encoder with around 50,000 pulses per revolution to get a .0005 resolution on a four inch radius. Does anyone know how modern lathes are set up for milling operations. Are there two systems including two spindle motor/drives and encoders? One for lower resolution high spindle speeds and another for low speed high accuracy? Does anyone have a brand new HAAS or Mori Seki I can take apart to find out? On Fri, 2007-11-30 at 17:29 +0000, Alan Condit wrote: > I want to be able to do threading on my cnc converted lathe. US Digital > doesn't > seem to make any encoder wheels of sufficient diameter to mount on the > spindle, > does this mean that I will have to either belt drive an encoder from the > spindle > or make my own encoder? > > I have some HP 256 count encoders but they don't have an index. Can I use a > single pulse wheel that is mounted on my lathe spindle with an optical switch > (functions as a tach) as the source of the index signal? > > Alan Alan, can you provide more information on what lathe you have and what you have done as part of the conversion? -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
