Re: HSM Tapping Machine Article

Hi Peter,

If you have a floating Z asis, like a spline shaft with and upper and
lower stop of some short distance, you would need to worry about
lifting the tap upon reversing. If it laid in the hole spinning,
there is a potential of a burr.

You could use a tap head, probably the best method, or make your own
by limiting rotaton of the tap via some clutch assembly, and by
controlling axial movement by some from of spring or cushion. That
should be strong enough to start the tap into the hole, and to pull
the tap out of the hole.

I do believe the range of force needed to start or lift the tap is
signifiganly less than the strength the tap would have once the
threads are engaged so there would be a pretty big window and the
spring would not interfere with the thread cutting action.

This seems so simple I.m surprised there is not a site that shows how
someone else did it. Of course, not everybody has spline shaft
laying around next to small low torque clutches.......


Dave

--- In CAD_CAM_EDM_DRO@y..., "Peter Homann" <peter.homann@a...> wrote:
> Marcus,
>
> Thanks for your reply. I guess the stepper is not Ideal. I want to
tap a lot
> of M3 (3mm) holes into either 4mm or 6mm thick aluminium. I would
assume
> that with a spiral (gun?) tap, I could tap it straight through if I
has a
> "floating Z head. The spindle would be primarily suppling the
rotational
> movement, the Z axis would not have to keep up with the Z movement
due to
> the floating head. The tap would "pull itself down as it taps.
>
> This way, the stepper driving the spindle only has to rotate the
tap enough
> times to tap the hole then reverse it back out.
>
> It's not ideal but I don't fancy getting RSI hand tapping the holes.
>
> Cheers,
>
> Peter Homann
> <mailto:peter.homann@a...>
> Work : +61 3 8530-7755
> Adacel Technologies Ltd Fax : +61 3 9596-
2960
> 250 Bay St, Brighton 3186, VIC, AUSTRALIA Mobile : 0421
601665
> http://www.adacel.com.au Australian Software Engineering
Excellence
>
>
> > -----Original Message-----
> > From: Marcus & Eva [mailto:implmex@a...]
> > Sent: Wednesday, 29 May 2002 12:36 PM
> > To: CAD_CAM_EDM_DRO@y...
> > Subject: Re: [CAD_CAM_EDM_DRO] Re: HSM Tapping Machine Article
> >
> >
> > Hi Peter:
> > I'd be worried about losing steps on the spindle or the Z
axis.
> > I'd also miss not being able to run the spindle up to decent
speeds.
> > (Steppers are not good at going fast).
> > Cheers
> >
> > Marcus
> >
> > ----- Original Message -----
> > From: "Peter Homann" <peter.homann@a...>
> > To: <CAD_CAM_EDM_DRO@y...>
> > Sent: Tuesday, May 28, 2002 5:42 PM
> > Subject: RE: [CAD_CAM_EDM_DRO] Re: HSM Tapping Machine Article
> >
> >
> > > Hi Doug,
> > >
> > > My original idea way to drive the spindle with a 4th axis
> > stepper motor.
> > >
> > > How do I build an axial tension and compression device. :-)
> > >
> > > Thanks,
> >
> > >
> > >
> > >
> > > Peter Homann
> >
> >
> >
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