Re: [CAD_CAM_EDM_DRO] re: probe design

Smoke wrote:

>
> I've got a design idea for that probe that any of you could make. I'll try
> to get it sketched up and posted this weekend.
>
> I'm not into electronics much any more but I'd like to know why you'd need
> to worry about large currents in the probe? Seems to me a very small
> current would work just as well. Just run the signal thru some kind of
> amplifier if necessary. Then you can build the entire assembly from copper
> and plastic. Use your CNC machines to make parts sized for your machine.
>
> I also seem to remember that, even tho' gold has the highest rating for
> current conduction, next choices would be (I think) aluminum, copper or
> brass. Steel would be rather far down the list.
>
> Smoke

Gold is used because of the non-tarnishing properties. High amp contacts
are self cleaning(sparks), "Dry contacts", alias very low amperage,
require a surface that stays clean, do NOT run more than a few milliamps
through a gold contact. Try a jewelry shop and check on selective gold
plating. Ed.