Re: How round are your milled parts?

I have a used cnc kneemill, .0005 is what I see and from past
experience with machine centers (new and used), thats about what to
expect for circular interpolating a hole or boss.

--- In CAD_CAM_EDM_DRO@y..., "doug98105" <dougrasmussen@c...> wrote:
> Group,
>
> Just out of curiousity, how round will your mill cut parts?
>
> I was making some flat plates, 1/8" thick, 6061-T6 aluminum.
> Different diameters, about 6" to 8.5". Using a .010" finish pass
> with a 3/8" diameter end mill, I'm getting from .0005 to .0012" out-
> of-roundness. Well within the customers tolerance of .002"+/- on
> diameter.
>
> My curiousity is aimed more at factory made CNC's or retrofits of
> factory machines, especially newer machines. For instance, how
> accurate are the new, low cost knee mills as they come from the
> factory?
>
> I know most home-brew setups can't be expected to hold close
> tolerances so I'm not particularily interested in those. But, it'd
> be interesting to hear stories if you have one that is very
accurate.
>
> BTW, I'm not asking how to tune my mill so it will make more
accurate
> circles. I know how to do that, it just isn't worth the effort on
> this 10 year old machine.
>
> thanks,
>
> Doug