Re: Asian Lathe Conversion

Just a note on lathe work.

before the CNC stuff, there was a device called a TRACER. it was a
hydraulic piston that held the cutter in place.

a template was made and the hydraulic sensor would move the piston as
needed to follow the template. very accurate, very repeatable. very
rugged.

I used one for years on production lathe work, and it would not be
hard to find such an animal in most any used machinery locations. I
have seen at least a dozen in the last year, and there is one on E-
bay now.

if you can make your template on your CNC mill, you can make pretty
much any shape. the lathe is stone cold stock, not mods. the Tracer
is nothing more than a tool holder. you still use your speeds and
feeds and the tracer allows you to control your cutting depth.

An option to making a complete CNC lathe is to use a DRO and control
only the cross slide as the dro feeds back location. it would only
effect one axis, you would gain the DRO and have that for use in all
aspects of the lathe.

just a few thoughts.

Dave





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "mayfieldtm <mayfiet@i...>"
<mayfiet@i...> wrote:

> Thanks everyone for all the good input.
>
> I really hate like heck to convert a nice new machine.
> Unless the conversion can be done in such a way to still allow me

to

> make use the gears for cutting treads, when desired. I would think
> that would be doable.
>
> Been shopping for a good used one for 6 months now.
> Most that I have seen have so many miles on them that proper
> restoration busts my $3000 budget.
> A highly recommended local dealer had a really nice looking,

freshly

> painted machine, with rails that looked new. However... a 12"
> straight edge showed at least .01" wear near the spindle end. It
> appears that someone had used a hone to remove the telltale ridge
> that appears on any used machine. So now I'm Jaded. So much for
> reputable dealers.
>
> I do have an alternate plan. What do you all think?
>
> I need to do a lot of turning using hyperbolic curves.
> That is why I want computer control in some form or other.
>
> I'm thinking that if I always make cuts toward the spindle, that,

any

> backlash in the lead screw, (X Axis) is not a problem. (possible

bite

> my butt assumption)
> I would convert only the cross feed screw, (Y Axis) to a servo

driven

> ball-screw and use a linear encoder for position reference on the
> lead screw.
> I will have to write a program that will read the linear scale and
> position the cross feed appropriately, on the fly.
> (not a problem)
> So this is not CNC in the traditional sense.
>
> OR!... Maybe I should make my own Compound with ball-screw and swap
> it out when needed?
>
> Tom M.
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "doug98105
> <dougrasmussen@c...>" <dougrasmussen@c...> wrote:
> > Tom,
> >
> > If your intention is to purchase for the sole purpose of
> > retrofitting, I think you should forget it. For less money you

can

> > buy any number of older NC lathes with dead controls. Hardinge
> > HNC's are one example.
> >
> > Regarding Asian machinery in general, you get what you pay for.

If

> > you're willing to pay the bucks you can get any quality level you
> > need. The vast majority of the world's high precision machine
> tools
> > are now made in Asia.
> >
> > Regarding used machinery, buy from a reputable dealer and you
> aren't
> > taking much risk. With the current state of the economy there're
> > some incredible bargains out there.
> >
> > My $.02 worth.
> >
> > Doug