Re: not stiff enough!

Richard,

Check out the method used / suggested by Dennis Bohlke at Super-Tech
Associates. The URL for this method is
http://www.super-tech.com/root/mechInfo/rodmounting.htm . This looks
like an interesting solution to mounting / supporting round guide
rails. The rails with pre-drilled holes every 4 inches are available
from MSC and McMaster-Carr.

John Guenther

--- In CAD_CAM_EDM_DRO@egroups.com, "Richard Spelling" <richard@s...>
wrote:

> I built this cncrouter:
> http://www.spellingbusiness.com/robot.jpg
>
> X is 1 1/4" shafts, 60".
> Y is 1" shafts, ~40"
> Z is 1/2" shafts, 18"
>
> The problem I'm having is that it's not very stiff. I realized there

would

> be some flex in the unsupported shafting when I built it, but I

didn't

> realize it would be as bad as it is.
>
> I have 3/4" for Z, which would take care of some of the stiffness

problem,

> but I can grab the top of the top of Z and move it by hand and the

1" shafts

> will flex visibly.
>
> My current back to the drawing board effort focuses around theses

items:

>
> 1) use the 3/4" shafting for Z
> 2) move the Y shafts further appart to reduce leverage
> 3) possibly rotate Y shafts 90 degress to bring the "top" one to the

same

> level as the bottom one
> 4) use the 1 1/4" shafting for Y
> 5) use the 1" shafting for X, drill and tap holes for support posts
>
> and maybe
> 6) use open bearings an ALL shafts, attach "angle iron" steel

supports and

> cross bracing.
>
> comments and suggestions requested!
>
>
>
> Richard Spelling, http://www.spellingbusiness.com/boats
> From the muddy waters of Oklahoma