"Bill Schwab" wrote in message
...
Hello all,

With respect to dial test indicators, I am struggling with understanding
auto-reverse. It appears to be good, but what is it? I see lots of
mention of not needing to flip a lever; are such indicators obsolete now?
Is there any reason one would want one?

I can't think of a reason.


It might help to start w/ my import's behavior: the dial advances
clockwise from zero regardless of the direction of motion of the point. It
looked weird at first (the dial markings suggest it would do something
else), but I figured it was probably by design, having something to do
with an indicator version of backlash near zero.

I'm not sure why they do this (I have one too) but I don't find it to be an
issue. You can't use both direcitons at the same time anyway...


When indicating a vise or a part, I use the cross travel to make contact
with the point and then continue moving to get a non-zero reading and work
relative to that. I don't bother to move the dial, though it might be
smart to "permanently" offset it so that I'm working at zero vs. 15.

15 is excessive. A preload of a couple of thou should more than suffice.


While not in the market right now, I am thinking ahead to a rotary table
and wondering how I am going to align it. A centering indicator is one
option, but it looks a little long for a mill-drill. I might be able to
make it work by mounting it in an R8 collet, bumping in the table, and
then changing back to my ER chuck for normal work. With the mill's dials
locked, (if needed) I could move the table to free up space under the
spindle, change, and then start work with the RT's axis at zero on the
dials.

Depending on what you're doing, there are a number of ways to setup a rotary
table. I don't think you need a centering indicator though (especially given
the price).

Typically you center the part on the rotary table first. Once that's done,
center the spindle over the rotary table.

Many people make tooling plates for their rotary tables so they can cut into
the table (only slightly) if required to mill a complicated profile. If you
make a tooling plate, you can place a dowel hole in the center and then use
a dowel pin to center the rotary table to the spindle. The part too, if you
can accomodate a dowel pin hole in it.


Is there an easier way? Is there another type of indicator I should
consider?

I'd recommend getting one that will reverse without flipping a lever. Levers
are annoying.

Regards,

Robin