Just an update, i will post the picture later of the settings and the electronics inside the box
Strange thing just happend that may help us solve this.
As i said before, the spindle runs when you use the claibrator in mach3, it sounds fine getting up to 8000 revs, then from 8000-23500 it sounds like its reving up and down slightly but doenst seem to speed up much. 22500 - 24000 it speeds up a bit I will post a picture of the calculated curve latter.
Here was the odd bit. Run a bit of code, it seems to run ok at one end of the table ( start the spindle, but not at the other end of the board, ( wont start the spindle )).
We then run the same code in the middle of these two points, and as soon as it travels past a certan point on the board, the spindle makes a funny noise but keeps running, as soon as it clears that point. the funny noise stops.
So, i then lifted the cable that are in the cable arm, and the noise does not come on. we tested this a few times with teh gcode was running.
I suspect that maybe there is some interfarence in the cable, we are going to re-check all these later on, re-rout the cable make sure there is no interfarence.
The calculated curve still looks odd though, i will post picture later.