Must admit that it can get confusing, IMHO, and below is my summary of the different axis motions as taken from the manuals.

If your indexing using the A then you would use steps per degree ( that's conventional in industry as i understand it).

You should find the velocity and acceleration which is appropriate for the A axis. So just using the A to index is somewhat straight forward.

Now if your going to slave the A to some axis then things get more complicated. Feedrate gets modified / blended / coardinated based on a radius that you can define in Mach and remember that the feerate may get restricted to the slowest axis based on velocity. A real kicker is when you want some feedrate, and it reverts to say A settings which are slower, but the feedrate is not realy linear; ie and you find that the feedarate is not actualy say doubling but rather is only increased by say 10%. For a stepper the torque is decreasing as the velocity is increasing so even though you call out for more velocity / feedrate but it physicaly can't do it, thus a slow physical feedrate. Good reason for a servo on the rotary........

So you can if you wish make the A movement be angular or linear and then axis movement changes depending on gcode, the feedrate mode,

etc. So take a look at G93, G94, and G95.

Co-ordinated Linear Motion (Section 10.1.5 in manual)

Co-ordinated linear motion - each axis moves at constant speed and all axes move from their starting positions to their end

positions at the same time, also defined as control the axes so that, at all times, each axis has completed

the same fraction of its required motion as the other axes

- IE; any two axes ( x,y or z ) produces motion in a straight line

- the motion can be done at prevailing or rapid feedrate and may default to the slower axis feedrate

FEEDRATE ( unless G93 is used ) Section 10.1.6 in manual

1. X, Y, Z + A, B, C - without simultaneous rotation - F =length / minute ( along the linear path )

2. X, Y, Z + A, B, C - with simultaneous rotation - F =length / minute ( for the XYZA combination linear path ~ modified F

based on a diameter)

3. X, Y, Z + A or B or C - with simultaneous rotation - F= Degrees / minute of A or B or C

3. X, Y, Z + A B C F= Degrees / minute using a blended ABC / conceptual angular motion

for total time

3 Feed Rate Modes - ( Section 10.7.25 in manual )

G93 - inverse time feed rate - F = 1/F# minutes ( if the F number is 2.0, the move should be completed in half a

Minute)

- if active, an F word must appear on every line which has a G1, G2, or G3 motion

- an F word on a line that does not have G1, G2, or G3 is ignored.

- does not affect G0 (rapid traverse) motions.

It is an error if: inverse time feed rate mode is active and a line with G1, G2, or G3

(explicitly or implicitly) does not have an F word

G94 - units per minute feed rate F= inches / minute, mm / minute, or degrees / minute, determined by length units are being

used and which axis or axes are moving

G95 units per rev feed rate F= number of inches / mm / degrees per spindle revolution, determined by what length units

are being used and which axis or axes are moving.

RICH