"Spehro Pefhany" wrote in message
...
On Wed, 25 Jan 2012 21:42:18 -0500, the renowned Ed Huntress
wrote:

On Wed, 25 Jan 2012 21:29:56 -0500, Spehro Pefhany
wrote:


Hi,

I've never used a DRO on a lathe, but often used a dial indicator on
the ways.

I'm thinking of adding a glass-scale (2 tenths resolution) DRO to at
least two axes.

Is the third axis worthwhile-- given extra cost and additional hassles
to install?

Assuming you're referring to the compound, most people would say "no."
When Mitutoyo was first selling its retrofit scales for engine lathes
I had a discussion with their technicians about the subject, since I
was thinking about doing it myself (I didn't; I decided to be a
traditionalist/hobbyist). They said that most people would find it to
be of little benefit.

I'm sure that some people use the compound in a way that they would
benefit from it, but the consensus was that most would not.

Now someone will come along and tell us all the ways he uses a scale
on his compound. d8-)

So far, it's unanimous-- rare on forums.

Thanks, gentlemen, I think I've made my decision.. the 2-axis choice
is from a less worrisome local supplier, so I'll go that way.



Its not needed on the compound...

For threading, set the compound dial to a convenient zero point then use the
cross slide and touch the work....now, set the cross slide dial not ot zero,
but to the double depth amount instead....( or in your case, set zero, move
off and dial in the double depth amoount and reset zero again ) now, back
off on the compound and then you can take all of your passes with the cross
slide always at zero on the dial, moving the compound inward by .005 or so
each pass till you get to zero on both your dials.