Re: DIY probing

Hi John,

Yep, sounds like a Renishaw! Quite a few threads on it a while back! I
went so far as to tear up a cheap ball bearing race to get some
bearings! I'm currently LEARNING how to digitize using the inexpensive
MaxNC digitizer. I'd guess it's constructed similarly, I haven't peeked
inside! ;>)

I'm better off writing SOFTWARE for the "digitizer project"! I'd be
curious to hear some of the uses of the probe (CM), and techniques.

Alan KM6VV


John Wasser wrote:

>
> --- In CAD_CAM_EDM_DRO@y..., ccs@m... wrote:
> > Anyone have plans or ideas for an inexpensive shop-built contact probe?
>
> I did a little research just today on digitizing probes to prepare for mak=
>
> ing one. The best source I found was the US Patent and Trademark Office:
>
> http://www.uspto.gov/patft/index.html
>
> Search for patents with "touch probe" in the title.
>
> The typical design uses three metal rods in a plane perpendicular to the pr=
>
> obe shaft and separated by 120°. The three rods are insulated from each oth=
>
> er and each rests on two contacts that form a roughly V-shaped notch (either=
>
> balls, cones or crossed rods). The members of each contact pair are insula=
>
> ted from each other and the three pairs are connected in series. The circui=
>
> t is closed as long as the three rods touch all six contacts. If the probe =
>
> is tilted even slightly in any direction one of the rods will lift away from=
>
> one of the contacts and open the circuit.
>
> One thing to work out is a guide system to make sure that no matter how far=
>
> the probe tilts it will settle back down with the rods against the contacts=
>
> .