On 2010-08-08, Wes wrote:
Ignoramus2412 wrote:

Our older cnc lathes with gear boxes require a M41 or M42 command to switch gear ranges.
Perhaps you could implemnet something similar where the command emits an output you use to
shift the sheave. IRRC M41-44 are typical gear change M codes.

Wes, yes, I would like to find some good G code number and then
implement it. I got some suggestions on emc-users on how to do it,
with comparator elements of EMC. But speed change should only happen
during speed change, and not at any other moment, like reversal or
whatnot. If I get it to work, it will be much better than VFD, and
will let me tap with relatively larger taps.

I have a question, does your lathe have a back gear much like a
manual Bridgeport? I've never seen a mill like yours.

My Clausing lathe does not have a back gear.

My Bridgeport Interact CNC mill does have a back gear, lowest it goes
is 60 RPM.

To some degree automating the sheave displacement should be lower on
your list unless you implement a tool changer. After all, you got
to change a tool manually now, not much effort to adjust the
sheaves.

Yes, but I could forget to change speed.

Are you planing a tool changer?

Definitely not, too complicated.

As far as keeping the varidrive, I went through a lot of effort to
repair the varidrive on my Clausing 6903 so I know where you are
coming from. How hard my lathe can work is limited by how hard I'm
willing to push the thing.

My own opinion, after the fact that I did it like you, is that it was
too much work and cost for not as much benefit. I did it
too. Varidrive on this mill, though, is workin well.

i