Re: [CAD_CAM_EDM_DRO] tram-it

Hi Bill,

You could be right! Must be more analog, so that the arc of light is
variable, and can be "tweaked". Good thoughts. I think I'd be afraid
of adjusting the column too much, and running into the table with the
device!

Alan KM6VV

Bill Phillips wrote:

>
> Alan and Jack,
> You have set a thought going. While working on customer returns of
> inductive transmission systems I found out that you could use the
> transmitter module as a very effective proximity detector. It was possible
> for instance to measure the thickness of ink on paper. Completely useless
> of course but it may be a similar technique is used on the Tram-it.
> Within the disc may be a coil of some sort driven by an oscillator. As it
> rotates over the metal of the table the coil characteristics will be
> modified. This can be picked up as a variation of amplitude or frequency
> and fed into some kind of logic which will modulate the LED's colour to
> suit. The closer the disc to the table the greater the change. Where it
> goes over the table edge or a slot the effect will be zero and the LED
> probably goes out.
> Of course I could be completely wrong. (as usual)
>
> Regards
> Bill Phillips
>
> >Hi Jack,
> >
> >I suspect reflective opto-switches. The kind used for Dan's tach's.
> >Several channels, driving LED's, around in a circle. I know, we can
> >build one!
> >
> >I'm still waiting for a Renishaw for my Sherline! Anybody build any? I
> >tried some experiments with a small microswitch mounted on a 1/4" rod,
> >and was able to nudge up to it, and get fair repeatability. Only good
> >for one axis, 'tho.
> >
> >Alan KM6VV
> >
> >
> >jmw@... wrote:
> >>
> >> Does anyone know how a Widget called Tram-It works? (I think I've got
> >> the name right.) Tram-It is supposed to help align the head of Bport
> >> type mills. The thing is basically a 4"-6" disk about 1/2" thick with
> >> a shank to mount it in the machine spindle.
> >>
> >> You fire up Tram-It, wind the mill to 500 or so RPM and bring the
> >> device about .050" from the table. The thing lights up around its
> >> periphery (via multi-color LED's I presume), one color in the highest
> >> zone and a second color elsewhere. You adjust the head until Tram-It
> >> glows just a single color all around its edge.
> >>
> >> A couple hundred $ is a little pricey when an indicator and bent rod
> >> work fine, but it's a bit of a head scratcher how the thing works.
> >>
> >> Flying .050" above the table, it wouldn't take me long to crash the
> >> disk. Also I think I'd prefer not to adjust the head when the machine
> >> is vibrating.
> >>
> >> But how does it work?
> >>
> >> Thanks in advance.
> >>
> >> --Jack