4th Axis Setup questions

[Smokingman]

I have some questions and some problems setting up a 4th axis and any help would be appreciated.

The Setup:

Rhinoceros 4.0
RhinoCAM 2.0
Mach 3
K2CNC

I just bought a 4th axis indexer from K2 and mounted it along the Y axis.
I believe I have it setup correctly in Mach 3. In other words 'G0 A360' will make exactly 1 revolution and G0 A0 will put it back.

Since I'm using axis A on the Y axis (as opposed to the default X axis) I edited the machine profile in Rhino CAM to swap A and B in the post processor. Is this the best way to do this? Or should I set it as B in Mach 3?

I did a test "Air" cut and everything seems to work except for the speed of the rotary axis. I set the feed rate to 45 in/min for the 4th axis roughing operation and it seems to be turning at 45 degrees/min.

Is there a way to get either RhinoCAD or Mach3 to properly calculate angular speeds or do I need to figure them out myself? Or did I miss something basic in my configuration?

Oh, one more thing. Should I zero my Z axis at the center of rotation? It seems to make the most sense to me so I wrote a macro to set it there based on a tool touch plate. Or is it more common to touch off the stock.

Thanks in advance!

[mredburn]

In Mach 3 under the "config" tab >toolpath > check the box for "use radius for feed rate". I have seen screens where it said use diameters but mine says use radius for feedrate. Try that and see if it helps.

I have different fixtures I use for milling on the rotary table . One I have has a 1.200 turned surface, I touch a tool to it and set Z at +.600. I have one that I set the tool to the z axis and zero it. It all depends on what im cutting and how and whether or not i have a tool change. . I have put stock in the chuck that was a known dimension and zeroed off 1 particular point. As long as you remember which one your doing where.

I was having the same problem and this thread got me off my duff to go find the answer.

Mike