RE: [CAD_CAM_EDM_DRO] How important are manual controls on CNC machines?

I have a Shoptask so this is from experience. The backlash in the fine
feed can be reduced to a much lower value than you currently have, but a
ball screw direct drive is even better.

I have a couple of machines that have only CNC control with no manual on
any of the axis. Once you get used to the idea that everything is from
the keyboard you do not miss the manual cranks at all.

Tim
[Denver, CO]
Sherline products at Deep Discount
Mach1 & DeskCNC with credit card ordering
www.KTMarketing.com/Sherline
Now selling Visual Mill

> -----Original Message-----
>
> Hi All:
>
> I have a Shoptask lathe/mill that I intend to convert to CNC.
> The machine has a fine quill feed that is intended to be
> driven by a stepper, but it is junk, with about 0.050 backlash.
>
> I recently bought a surplus anti-backlash ballscrew
> (preloaded dual nut) that is long enough for the quill. Last night I
> finally sat down and designed the mount for it. The screw
> is attached to the quill, and does not rotate. The nut is
> attached to the millhead, runs in a double row angular
> contact bearing, and is rotated by a timing belt pulley (2:1
> reduction from the stepper).
>
> The original fine feed shaft is parallel to the table. It
> has a hand crank as well as the pulley, and could easily be
> used manually when the stepper is turned off.
>
> WIth the new design, the ballscrew and the stepper shaft are
> both parallel to the quill (vertical). It will be very hard
> or impossible to provide a hand crank in the available space.
>
> Am I going to regret not having manual control of the quill?
>
> I do have a scrounged jog wheel, which I intend to hook up to
> my CNC system. So when the system is powered up, I can still
> move the quill easily. But it will be very difficult to
> adjust the quill when the CNC system is turned off.
>
> John Kasunich