Re: [CAD_CAM_EDM_DRO] tram-it

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
>