4th Axis Steps per Inch?

[mr.c]

I am not sure that this will be of any help,but here is what I have done with my rotary. I have set it up so that one revolution is equal to 36" .  That allows me to use degrees by simply subtracting a decimal place from  the inches. In other words, 90 degrees would be 9" and 275degrees would be27.5 inches. One degree would be .1"   10 degrees is one inch. Half a degree would be .05"
Does that make since? Helpful?

[RICH]

Does that make since? Helpful?

Hmm....stay with STEPS / DEGREE for indexing as suggested. You want to move 90 degrees you code G0 (or G01 with a feed rate) A90.0 ...whats so hard about that.

It "could" make sense if you were slaving the rotary axis and making coordinated linear moves around a 36" piece.
If you use a stepper you will find that the feed rate will vary / won't be true / is not linear......

I wouldn't make simple indexing complicated, but ,.....do as ya wish

RICH

[mr.c]

Rich: I guess that I was in a hurry to get the rotary set up to do a job and did it that way so that I could keep up with where I was with the axis DRO for a multiple pass. That was the only job that I have needed the rotary axis so far.
 Will the axis DRO indicate position in degrees? I  have to admit that learning G-code for me is in a "as needed" format. I find myself having to relearn a lot of it if there is an extended period of time between useage. I have to relearn my cad programs if I don't use them often. It is a pain. Age has not been kind to me. I can remember the way I set my rotary up but would need to study to do it differently(the right way). I do need to set it up properly and write everything down so that I can pick it up again . The feedrate issue would be a good reason to do that. I may call on you for help later on. You are in Gainesville?

[ger21]

Mr C, your with your method, you could get some strange feedrate issues. Using steps/degree, and setting the part radius, you'll get a consistent feedrate regardless of the radius of the part.