Re: Opinions on $250 cnc machine

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<dave_mucha@y...> wrote:

>
>
> > I've
> > been using easily replacable "snap-in" polyethylene nuts -no backlash
> > on the only one I've had to use...It's just a 1" cube drilled &
> > tapped.
> >
> > Before I get in any trouble let me say that I'm here to share
> > and get experienced opinions on something I'm positive will
> > benefit all. I haven't seen this stuff used and it should be.
> >
> > I built a disc finisher (polishing machine) 10 years ago out of it
> > and have used it 15 hrs a week every since.
> >
> > My first lathe was cast on the end of an old blower motor.
> > I made actual usable roller bearings out of the stuff.
> >
> > I,d like to make a sortof "snap-together" customizable
> > cnc kit and I have.
> >
> > I do want my idea critiqued, critisized, and taken apart
> > because the thing HAS to work.
> >
> > Thanks -John
> >
>
> One thing at a time.
>
> you will deffinatly find a lot of people telling you it cannot work.
> IIRC, John K. and his machines with all-thread cannot work. the
> hundreds or so now running prove otherwise.
>
> Disregard the doom-sayers and focus on what you know will work.
>
> I am curious about the plastics. All the plastics I have seen in such
> large sizes are expensive. How do you get by without the high costs ?
>
> One can buy co8unter top at many local stores so that could be one
> option. Melamine shelving can be layered to make a very thick
> material, another option.
>
> I would not foucus on the super strong base as there are sooo many
> mancines with plywood or pressboard as the base that do work.
>
> Besides, a simple frame, a bag of concrete and some water and the home
> shop guy can make his own custom base, complete with Tee slots and
> vauume holes and even embedded nuts.
>
> Dave
>

Dave

Yeah I've seen what's been said about John K. for years now.

But his stuff DOES work.

I get by with cost because I cast mine myself. I've been working
with this stuff since 1989. You buy a drum of it and make aluminum
molds to cast a big block of it...them machine it to shape.

If I drill a hole in a block of aluminum and I'm off .010 then I
have to start over. with this stuff ,I can fix that hole and it's
as if it were never there.

I have machined images so small and fine on my prototype that
you actually must use a magnifying glass to see the details.

I'm not kidding about that either. my camera won't do pics that
small though i'd love to show them.

There are many different grades of castable polyurethane

and it ain't cheap for the good stuff, but it has many, many
uses for cnc.

Thanks -John