Re: Sanity check for homebrew CNC milling machine

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "skykotech" <rick@s...> wrote:

> Don't know about using mdf, might work, but i would not keep the
> completed gantry (bridge in england?) mill in a humid environment.
> One thing I found curious is how you plan to support the linear
> ways shafting in the middle? Do you have split bearings that
> travel on the shaft? If so, then you should probably support the
> shaft in several places...you wouldn't believe the amount of flex
> you can get by pressing in the middle of a 18 inch 3/4 inch
> stainless steel shaft supported at each end. If you don't have
> split bearings, I am REALLY curious how you would support the shaft
> at anything other than the ends.
>
> Richard

...and...

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "vavaroutsos" wrote:
> Arvid, take a look at some of the designs offered from the likes of
> www.campbelldesigns.com and others if you haven't already. I think
> you could build a better machine from aluminum extrusions for not
> much more money than MDF. You want the rigidity on the bridge, but
> not the weight as F=MA.


This is a fixed bridge, moving table construction - not a moving
gantry machine. So the weight of the bridge will be not be a problem -
on the contrary, as it will help reduce vibrations.

Also, since I can make the length of the table longer than the travel
of the table, I can support the bars at the middle. I could get even
more travel without this extra support, but I think it will be needed.

Arvid