Re: Re: Re: Limit Switches ???

John

The crashes you describe are why somebody invented software chuck barriers.
software. Lathes are much more of a problem in this regard than are mills.
IMHO the purpose of limits is not to prevent the tool from going through a
part of the machine that it is not supposed to, rather it is to prevent the
ball nuts and slideways from being wrecked by overtravel.

Ray

>    From: "John" <johnhe-uk@...>
> Subject: Re: Re: Limit Switches ???
>
> I don't really see the use of limits switches unless you're using it to
> find home. I have two on my lathe, one is right down the headstock end of
> the machine and the other is on the X axis. On the X axis there is a
> tapered rod inside that is connected to the cross-slide. If it move too far
> in or if it moves too far out it cuts the power. On the Z however the
> switch is at the headstock only.
>
> Right, but now the limit on the headstock end is so far up towards the
> headstock I can crash the carridge into the chuck while it's spinning. The
> switch only prevents a non-toolposterised cross-slide from passing under
> it. When it reaches the switch nothing much happens (It may be bust but
> it's barely been used). With a toolpost on though the carridge will travel
> into the headstock no trouble. What's seriously annoying though is that the
> X axis [towards and away from you] does genuinely turn it's motor off
> before the slide reaches it's extremes.