Re: [CAD_CAM_EDM_DRO] Re: 14x40 lathe conversion- Carriage drive help?

Hi,

On my machine the Z axis is driven by stepper via the screw cutting leadscrew. Although the machine is 25 years old it was like new when I got it. I have used it for about 8 years nearly every day and there is no great wear on the leadscrew or half nuts. I've never had to find out what the lead is but I would think it is about 6 TPI and I have no problem with taking a 1/4" cut with a sharp tool.

I still have not fitted a cross-slide ballscrew but only regret this once a week, it is on my list of things to do.

BTW. My lathe is 11"x36" and was built to train CNC lathe operators in technical schools.

Regards,

Terry



I understand. How do I drive the Z azis then? The rack and
pinion is very course and very sloppy. Do I use the threading
screw? Not much meat on the split nut of that thing. I am afraid
that I would wear it out in a hurry. Do I just get new ACME
screw and nut to drive carriage? Of course, I would prefer
to use what I have.
I was figuring on picking up a ballscrew on E-pay for less than
$300 for the X-axis. Hopefully, much less.
Ballscrewing the cross slide is pretty much a
"must do" for me.

Thanks,
Scott





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Terry Owens" <jo001k1132@...>
wrote:

>
> Hi,
>
> Why do you need a ballscrew on the Z axis when the convention is

always to cut towards the chuck? I have a Harrison 280 CNC, which was
manufactured without ballscrews at a price at the time which would buy
two houses in my area.

>
> I must say I would like a ballscrew on the cross-slide, as it is

much more difficult to creatively program to take up the backlash on
this axis.

>
> Regards,
>
> Terry
>
>
>
> Can't help it. I have the bug.
> Now that my BP is closing in on
> completion I am thinking about
> gathering what I need to do my lathe.
> It is a Grizzly 14x40.
> My question is mounting the ballscrews.
> I guess I can machine a block to hold
> the ballnut on the carriage- behind the
> carriage apron- where the ACME threading
> screw is. Then mount the ballscrew's
> right end in a block with a pair of angular
> contact bearings holding it in place.
> Now is it just best to let the left end
> of the ballscrew just float?
> The legnth of ballscrew I need is over 50".
> What diameter is appropriate?
> Anyone have any pictures of a conversion of a
> lathe like this?
>
>
> Thanks,
> Scott
>
>
> [Non-text portions of this message have been removed]
>

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