Re: not stiff enough!

Very interesting... I don't see any reason I can't take some of the
skills from my boatbuilding obsession...

Use a good marine ply for the webing/rail attachment, bed the rail in
an epoxy-wood flour mix, and use angle-iron instead of aluminum
angle...

Seal the wood in a couple of coats of marine epoxy to reduce water
absorbsion...

--- In CAD_CAM_EDM_DRO@egroups.com, "John D. Guenther"
<jguenther@l...> wrote:

> 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