Re: Linear bearing types?

On Tue, 25 May 1999 23:41:47 -0500, Jon Elson <jmelson@...> wrote:

>Right - and you'd have a very flimsy machine, which wouldn't be able
>to cut anything tougher than cardboard or modeling wax. Some people
>want a machine like that. But, as a (converted) Bridgeport user, who
>still has problems with rigidity sometimes, I can't imagine how something
>with 1/2" or 3/4" round rails would work for metal cutting.

Yes, I think this approach to answering "what-ifs" will go along way to making
our group successful and peaceful. Because SOME PEOPLE DO want/can-use such a
positioning system to cut foam, wax, or Rayite. (or maybe even cardboard/mdf)

Also, you'll see from time2time guys wanting to ROUTE thin alum sheet to size,
but NOT to +-0.001 precision. You've just gotta appreciate that there are all
kinds of aspirations and users for this CNC stuff, and by comparing notes and
caveats, we can help each other enormously to putting boundsNbrackets on what's
doable with a given mass/stiffness/HP whatever. AND this exercise builds
comprehensive understanding.

In lieu of some "scientific" metric or engineering design for each requirement,
comments like this give each of us an idea of the rough boundaries we're dealing
with, as far as stiffness, guide and positioning precision, etc.

My vote is for us to strive to NOT pooh-pooh another's applications that might
sound either flimsy (or overkill) compared to our own interests, but instead, to
develop a "feel" for how/what might be sufficient in terms of guide hardware,
positioning screws, driver electrics, and even software programs. That way we
all get a broader view of CNC metrics.

We've got a tremendously diverse set of interests/users on this group, and a
wise person (oh please, let that be me at least :) wanting to learn the max,
could easily build a MUCH broader understanding of what works with what and for
what, by tryna see what HAS worked for people in the past, and what's being put
together for the future.

And if from time2time, someone has to be the bearer of "bad news" as far as a
particular aspiration being outside the realm of physical reality, well, we can
all learn from that too, eh?

Gar