Just joined, hobby level

[cncgcg]

Hi Tom,
Thanks for the reply,
Have you ever tried a bowl shape?. I have been thinking about the trig for this for a while now. I remember seeing a G code routine doing something similar and it used Tan, but the way I visualise it you only need to mill repeated circle pockets moving inward with Z increasing down as it moves inward, which is also calculated with Cos or Sin and not Tan. Doing it this way makes it easier for me to also generate a scaled curve rather than a pure circular one i.e much deeper or shallower as required. If you look at my program you will see what I mean about scaling the arc.
By scaling I mean ellipse, it's just my word for it since the program produces elliptical arcs depending on the X,Y scaling. Can you follow me?
Here is the program, take a look at Arc, click the Arc button, drag the mouse in the drawing area to make the shape appear and scale X,Y to say 100, 45 and a sweep angle of 180 degrees. yes it's mm's, I got metrified years ago sorry

http://cnc-gcode-software.com/wp27

Gareth