Re: updating to Ball screws

Jan,

You are exactly correct. If you do not USE the handwheeels of the
CNC-ed tool, there is no reason (beyond economics) to prefer rh or lh
thread.

The original poster wanted that "duz-all" manual/cnc COMBO MILLing
machine.

Also, on many lathes, the crossslide screw is rh. Top, or compound is
sometimes lh; and carriage feed leadscrew can be either way, as it is
not usually (Sherline and similar are exceptions) hand driven. A
rack/pinion is used for non-precise carriage moves (Here, taig is the
exception, having ONLY a rack/pinion carriage drive). Lathes seem to
have much more variation of the SCREWS (the wheels still move in the
"expected machinist" direction(s).

Hope this helps.

Ballendo

P.S. Troll, Do you share origins with the ill-fated character in the
new Harry Potter film? :-)

--- In CAD_CAM_EDM_DRO@y..., JanRwl@A... wrote:
> Ballendo: Perhaps it is due to my own questionable genetic origins,
but I
> have built four, now, "CNC" lathes (application-specific), using
"ordinary"
> RH (ACME) screws, and actually have no difficulty at all, going
between the
> ordinary "engine lathe" and the CNC home-brew machines. Perhaps
primarily
> because I almost-never turn the handwheels on the "CNC" machines, as
that's
> the computer's job, after all. But both the X and Z screws turn
"opposite"
> from most manual machines. Oh, and the "Z" handwheel is not on the
apron, as
> it would be on most manual machines, but is on the END of the long Z
screw,
> on the far-right.
>
> Regards! Jan Rowland, Troll
>