Re: Mill/Drill CNC Conversion

Hi Jeff,

Thanks for the reply. Maybe I'll take mine apart, just to get a "feel"
for it! That doesn't sound too bad for ballscrews! And I like the idea
of using the cheap nuts first, then one can graduate to the expensive
ones later... if wanted!

Still, it all adds up. I'm tempted to just make up some motor mounts,
and try driving the acme screws for a while! I think I'd learn quite a
bit that way.

Fred has a good deal on the Vector CAD only package, a good way to get
your CAD started! I'd sure like to see some parts drawings! Also
remember the other free CAD packages. And even the local discount
stores (CostCo?) have a TurboCAD for about $25, with a tutorial!

Cincinnati is a little to far from the West coast! Sure like to see
more!

Alan KM6VV


jeffswayze wrote:

>
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV
> <KM6VV@a...> wrote:
> > Hi Jeff,
> >
> > Thanks very much for posting the pix! I've been wanting to get
> a better
> > view of what needs to be done to convert the mill. I assume
> you've got
> > access to another mill, so that you can make parts without
> having to put
> > the mill back together! That's what I was dreading! Have you
> made CAD
>
> Basically what I did was to measure EVERYTHING on the mill
> first and make drawings (no CAD yet, but I'll create and post
> them in the future.) I had to take the table apart and put it together
> 3 or 4 times, but I must say I got pretty good at it by the end. Not a
> big deal, really.
>
> > drawings of the parts? I'd also like to get a rough idea of the
> prices
> > for the ballscrews and angular bearings.
>
> Bearings were about $12 each (and I may have a few left over, if
> you're interested), ballscrews were $?? from Reid Tool
> (McMaster-Carr is about $1.00/inch, Reid was cheaper) Ball nuts
> were about $23 each, but they are not pre-loaded
> (non-backlash). The pre-loaded ones are about $160 (!) each.
> For my initial test of the Y-axis, there was no discernable
> backlash, but I'll have to wait to put an indicator on the table
> before I know the exact backlash number.
>
> >
> > You had to bore the ends of the ballscrews? What does this
> involve?
>
> Actually a piece of cake. I cut the screws to length (it comes as
> one piece) on a cut-off saw, then used my 7x12 mini-lathe to drill
> and bore a hole in the end. For the longer (X-Axis) screw I had
> my friend bore the holes on his large lathe.
>
> > Something that one who's first full sized machine is the RF-31
> could
> > accomplish? I don't yet have a 9x20 lathe. Perhaps the
> ballscrews can
> > be ordered that way? Can you explain the "stub shafts" that are
> > "pinned" in the end of the ballscrews?
>
> You can order the screws pre-cut and machined, but it's fairly
> expensive, and being the frugal (and now broke) home
> machinist I decided to do everything myself. The stub shafts take
> the place of the machined ballscrew ends and have features for
> keyways, bearing diameters, and threads. Though you could
> attach the two together with a shaft-lock compound from Locktite,
> I chose to pin mine together with a roll pin. I had to use a solid
> carbide center drill to get the hole started in the ball screw, but it
> did a pretty good job.
>
> >
> > This is all "big stuff" to my little shop. SO, my RF-31 will have to
> > "upgrade" itself!
> >
> > I suspect that a "RF-31 retrofit kit" such as you've done would
> be a
> > good product for this list (and the mill-drill list)!
> >
> > Alan KM6VV
> > P.S. What area of the country are located in?
>
> I'm in Cincinnati, OH.
>
> Good luck!
>
> -Jeff