not stiff enough!

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