Re: Lathe Encoders

Thanks, Jon & Drew
Tonight I checked with a dial indicator & clocked out to .1574"
or 4mm. Not as obvious as it seems because the screw is
.8 mm threads (once I found my metric thread gauge) multiple start.
I haven't had the nuts off it yet, but whatever they used works
great, as I can't see any backlash at all on the indicator.
Is a 400 line encoder enough,for the crosslide?
The carriage will get twice the counts, I think you would want more
on the crosslide. What about using 2 different counts, or is that
a no-no? The only reason I can see why they mounted the encoders
(resolvers) where they did is to save space as the crosslide servo
already hangs out quite a ways. Just trying to get the best
resolution, as these machines don't seem to have any wear on them
at all...nice and tight.

John Mesh

> John,

>
> Not sure if this helps or not but 6.125 turns per inch is a pitch

of

> about 0.16327" per turn. This is close to 4mm per turn and given

the

> lathes were built in Austrailia you might have metric leadscrews.
> Knowing this may help you get a little closer to figuring out what
> you really need in the way of an encoder.
>
> Drew
>
> John Mesh wrote:
> > Hi all,
> > Once again I need your expert advice on encoders.
> > I have 2 small Hercus Compulathes - CNC lathes that I am trying

to

> > convert
> > over to PC control. Currently, both of them have resolvers.
> > Would like to put 320 Gecko's and encoders on them.
> > My question is, what CPR for the encoders.
> > Here is the encoders that I would like to buy . (H1 series)
> > http://www.usdigital.com/products/h1h3/
> > On the X axis (cross slide) the encoder is attached direct to

the

> > screw.
> > About 6.125 turns moves the crossilide 1"
> > On the Z axis (carriage) the encoder is mounted on the end of
> > the servomotor. About 12.25 turns gives me 1" of travel, as the

motor

> > drives the screw with 2:1 ratio with a cogged belt.
> >
> [snip]
> > P.S. Lathes can be viewed at:
> > http://cgi.ebay.com/ws/ebayISAPI.dll?
> >

ViewItem&item=2515397279&indexURL=0&photoDisplayType=2#ebaylargephoto

> > hosting
> > The ANCA control, seems to be one hell of a unit, unfortunately

its

> > dead in the water.........
> > Anybody need some used ANCA parts?
> >
> >
> >
> > Thanks in advance,
> > John Mesh
> > jmesh@h...
> >
> >
> >
> --
> Drew Rogge
> drew@p...