Re: Sherline Auto Tool Changer

Ballendo;

Now, we're getting somewhere !

Hmm, you're right, the sherline collet is 'handy' cos it ready made
and seems like the logical choice, but the spindle locking and
undoing the holder is a problem, you're right that it would be very
difficult to undo, that was at the back of my mind, I guess I just
did not want to acknowledge it !!!

The current morse 1 taper limits the collet and cutter size as it
assumes that the cutter will locate inside the spindle, but there's
no reason why an adaptor can not fit on the end on the spindle and
interface to a quick change tool, I think there would still be
sufficient Z travel even with an adaptor on the end of the spindle.

We have gone through the first rule of troubleshooting which is to
elimante what it isn't (can't be done) now we only have to find what
can - so it should be plain sailing from here on in :-)

PeterC



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo <ballendo@y...>"
<ballendo@y...> wrote:

> Terry,
>
> Most fully automatic changers use a similar technique.
>
> Tools are held in vee-shaped non locking single taper holders.

There

> is a retention knob at the top of the holder, which is the small

end

> of the vee shape. Fingers inside the spindle are designed to

capture

> this knob and pull it upward (often using belleville washers for
> the "drawing in" force). The interior of the spindle is shaped so
> that thes fingers lock in a failsafe way (as long as the retention
> knob doesn't break of where it screws into the holder... Yes, it
> happens).
>
> To change tools, hydraulic or air pressure is used to compress the
> belleville washers, which drops the fingers a bit, which allows

them

> to come out of the failsafe recess, which lets them release the
> retention knob, which allows the holder to drop out (into a
> waiting "transfer arm", or into the lazy susan itself.
>
> Hope this makes sense,
>
> Ballendo
>
> P.S. Do a search of "CAT 40 holder", to see one of these holders
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "James Owens"
> <wotisname@l...> wrote:
> > Hi Peter,
> >
> > This is the bit I'm asking about. I'm a where how manual change
> millers hold
> > the tooling/holder in place. I have a Bridgeport type machine.

The

> question
> > is how do auto-changers, when they are fully automatic, hold the
> tooling in
> > the spindle. I can change a tool in a few seconds but I have to

be

> there to
> > do it. So if it is necessary for me to tighten a draw-bar why

use an

> > auto-changer when the tooling held in a lazy-susan would do?
> >
> > > The sherline tool holder simply screws into the spindle on a

high

> > > precision thread & shoulder. There's a 3mm hole in the tool

holder

> > > which allows you to locate in the holder to unscrew it.

Sherline

> > > claim that as the thread and location hole for the cutter

shank

> are
> > > created without removing the piece from the machine, that the
> > > accuracy is very high !
> > >
> > > I know that full size CNCs use a draw bar to pull the tool

holder

> up
> > > against the taper and locate it onto a dog, but I am trying to
> think
> > > of a way of using the existing available stuff.
> > >
> > > Another way would be to make an adaptor to fit the Spindle and
> then
> > > make special tool holders to fit the adaptor.
> >
> > Regards,
> >
> > Terry