Re: manual quill movement

Larry Van Duyn wrote:

> From: Larry Van Duyn <lvanduyn@...>
>
> Jon Elson wrote:
>
> >
> > See my photos, etc. at http://ascc.artsci.wustl.edu/~jmelson/CNCconv.html
> > look at the 8th picture for the quill (Z-axis) drive. There are other pictures of my CNC
> > conversion there.
> >
> > Jon
>
> This looks very similar to the design presented in the RCM drop box. One question comes to mind - how do you ( or can you )
> disconnect the mechanism for manual use. Since I haven't the space to park another mill, the current machine must serve both as
> manual and CNC.

Yup, I think this guy put those pics there just when I was getting ready to tackle the Z axis, and it was very much along the line I
had been thinking, so he sent me
some further details of which attach points he used, and I went from there. Mine is a horrendous kluge, because
I made a number of measurement errors due to the very difficult shape of the exterior of the J head. I ended up
having to mill out a bunch of holes oval, and put the whole mechanism about 1/2" farther out from the quill, so the
encoder would clear the belt housing.

I have no easy way to disconnect it from the quill, and I have the rack pinion gear pulled out completely.
I would have to completely disassemble the thing because the leadscrew blocks access to the bolt that
holds the nut to the quill, just like the stop rod does in the original Bridgeport setup. I wanted to make that
link as stiff as possible, to minimize any rocking of the link that would result in more backlash. I could have
made the link in several pieces, so that a piece of it could be unclamped, to revert to a manual quill.
I used to do tapping in the machine, when the quill could be allowed to slide freely. That is really the
only function I have lost by completely giving up manual quill movement.

I can move the X axis pretty easily, since the screw shaft sticks out the left end. The Y and Z axes can
be moved by turning the belt sprockets by hand, but I rarely need to do so.

Jon