On Tue, 25 Nov 2008 17:51:52 -0800, "Michael Koblic"
wrote:

The new vise arrived today. Eagerly I clamped it to the table and had at it
with my indicator (NB - *not* a test indicator). After much effort I got it
down to 2/1000" in 2" which is not great but I could not seem to do better.
Anyway, for the job in mind I was not too concerned.

The work went swimmingly: It involved drilling three holes down the center
of a 2.5" piece of a 7/16" key stock. I laid out the centres just to be sure
and used a centre finder on the first one - center drilled, drilled, repeat
three times by moving the Y-axis with the X-axis locked.

To my surprise the holes came out on a diagonal. Very slight but noticeable
to a naked eye and confirmed by measurement - and not a subtle 0.002"
either!

The only reason I can think of is that I screwed up the vise alignment
(duh!) but why? Is it because the indicator is attached to the spindle in a
drill chuck and the spindle has a freedom to move with every adjustment to
the vise I make? I have seen this procedure on two videos and unless I am
missing something everyone does it this way, i.e. indicator in a chuck.

Maybe I should repeat with the indicator on a mag base somewhere independent
of the spindle? What do you guys do?

Clamp around the quill, not the spindle. if you have to, use a hose
clamp and a bit of strap to make something to hang your indicator from.

that is what I do. On the other hand..you can indeed chuck your
indicator in a drill chuck..but put the spindle into lock mode...with
the motor off, put it i n the lowerst gear you have. less likely for
the spindle to turn. Its pretty sure that your spindle turned while
you were indicating.

Or your mill is way way way out of alighment G

Gunner

"They couldn't hit an elephant at this dist..."
Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania