Re: How to Make a Simple CNC Machine

Hi,
The unit is turning out custom keychains made from different
colors of plastic. The unit will do wood, plastic and wax. As for
backlash lets not go there! Backlash is a thing you worry about on a
real milling machine. On a machine costing under $125 you have to live
with it. The machine is a working model. I fail to beleive a 50oz
stepping motor can bend a 1/4-20 rod. The rubber tubing linkage works
just fine. You can use aluminum with setscrews. I have a lathe to
make
them but do other people?



John

--- In CAD_CAM_EDM_DRO@egroups.com, Jon Elson <jmelson@a...> wrote:
>
>
> kleinbauer@j... wrote:
>
> > Hi Alvaro,
> > Thanks for the kind words. My booklet has a over 50
computer
> >
> > drawing....others plans don't even come close. Who needs a $150
> > leadscrew when a $2 piece of 1/4-20 threaded rod will work.
>
> Well, even on a machine as small as the one you describe, there may
> be significant bowing of the leadscrew (unless it is placed under
> considerable
> tension). Do you have something to eliminate backlash?
>
> What is the overall accuracy of the 1/4-20 rod?
>
> > I use a
> > one inch piece of rubber tubing to couple the motor to the
threaded
> > rod.
>
> How rigid in torsion is that rubber tubing? Or, do you really use
some
> stiff
> plastic tubing? That might be pretty good, but if you really use
> RUBBER, it
> might allow quite a few steps worth of twist to develop between the
> motor
> and leadscrew.
>
> Jon