RE: [CAD_CAM_EDM_DRO] Machine mounted Tachometer with Surface Meter Per minuteThis

I thought I said 'gear tooth sensor' somewhere... Anyway, I doubt this'll
work off the nut as there may not be enough metal going past (esp @ 30k
rpm). You'll only pick up the 'corner' or the number 6 times per
revolution.

One flat shiny & the rest dull on the nut will work for optical if you can
sort out dust & plunging issues.

Tony

> In order for this to work, you need a gear tooth sensor, which is a
> hall
> effect sensor with a built in biasing magnet. It will read High when
> there
> is ferrous metal 0.5-2mm from the sensor
>
> On Sat, Sep 11, 2010 at 03:05, Tony Smith <ajsmith@...>
> wrote:
>
> >
> >
> > > > Most routers have a nut at the collet. If using non-ferrous
> metals
> > > (or
> > > > wood or plastic), a hall effect sensor can pick up the points or
> cuts
> > > > (for ER type collets.)
> > >
> > > Can you elaborate a little on how this would work since Hall effect
> > > sensors
> > > are only sensitive to change in magnetic field.
> > > Gaston
> >
> > Google 'gear tooth sensor'. The datasheet for the hall effect sensors
> > usually have this as well.
> >
> > The sensor can pick up the difference between air & steel, if you're
> got a
> > gear with big enough teeth, it can pick when it's moving. Not sure
> it'd
> > work with the nut though.
> >
> > Tony