Re: [CAD_CAM_EDM_DRO] arc or curve fitting program

Some time ago I sent a "letter to the editor" to Home Shop Machinist that
covered this in detail. A sketch was provided along with the required
formulas. It's really very simple. Maybe someone has a back issue and can
find it for you? The back issue will be somewhere in the early 90's as it
was printed while I was still in gunsmithing school (I think).

BTW...you don't need calculus. It can be solved with ordinary trig.
Smoke

> I'm taking some careful measurements on a part I'm reverse
> engineering.
>
> Given three, or more, points on a curve. How do I calculate the best
> G02/G03 parameters to cut that curve? I'm hoping for a simple windows
> app. that lets you put in points and gives the center and radius of
> the circle fitting those points the best. Also, I'll need to be able
> to calculate x,y points on that curve (you need endpoints in G02 and
> I'll not be able to measure right at the endpoint). Is the formula
> r**2 = (y - a)**2 + (x - b)**2 ?
>
> I remember covering this in calculus class 30 years ago, but the only
> reason I got through calculus was due to a very smart girl that let
> me sit right next to her, very near her paper, during quizes.
> Fortunately my eyes had great distance vision at that time <G>
>
>
> Karl