Re: manual quill movement

Larry Van Duyn wrote:

> From: Larry Van Duyn <lvanduyn@...>
>
> > 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.
> >
>
> That is one function which I use a lot. Since I have a VFD on the machine with almost instananeous reverse at low speeds, I power
> tap almost everything - down to a #2 and probably have even done some #1 stuff.

Yup, I had a lot of tapping to do, and did it the hard way. I'm thinking of making a tap driver that
has a slide and an overload clutch. Someday, I'd like to put a spindle encoder on it, and do hard
power tapping.

> > 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.
> One thought ocurred to me while reading some of the responses to this thread. Since ball screws will back drive quite easily, how
> about just removing the drive belt in an arrangement like yours when you want to go manual. The belt could be set up with an idler
> pulley on a cam which would make removing the belt quick and easy...

I have a .1" lead ballscrew, and it is quite stiff. I don't think anything less than a 1/4-20 tap would move the
quill at all, and that would still probably mung up the threads.

Jon