Re: [CAD_CAM_EDM_DRO] Re: Measuring backlash with a ohm meter

Chuck Rice wrote:

>I would be interested to know what the spindle to table resistance is
>on a bigger machine.
>
>The reason I tried this is because I am just learning to use a dial
>indicator and wanted another check. :) -Chuck-
>

Interesting question.

On my Bridgeport, it's about 0.3 ohms (0.299, actually) from an aluminum
workpiece to an endmill in a collet.

I'm not sure that any reasonably priced system would be able to
differentiate between this and a "dead short" with any speed. You
actually need a pretty good meter to get an accurate measurement in this
range.

I suspect that the electronic edge finders either use an insulated tip,
or use some capacitive sensing method.

- Steve