"Bill Schwab" wrote in message
ink.net...
Harold,
snip--

I think I follow. It gets to another question, which is whether you
work in absolute or relative (rezeroing) the dials? It sounds as though
you do not rezero. In that case, a "lap counter" would be handy, but
the scale probably does pretty much that.

Once you've set a dial, don't reset it while you're running the part, or
series of identical parts. It's too easy to screw up by a few thou.
Naturally, when there's no alternative, do so, but be careful you don't
introduce backlash while spinning the dial to the new setting. Then
remember you've lost your datum point, so the dial will no longer be in sync
with it.

Yes, the scale serves as a lap counter in a sense. What you'll find is
that when you have to step off inches, you count turns, 5/inch. If your
machine has dials calibrated .200"/turn, it's real easy to work in
thousandths, which I assume you do. Smaller mills often have dials that
are .125"/turn. They make it a little harder because you can't read your
dimensions directly as you can with the .200 dials (for example, 7/16" is 2
turns + 37 on the dial, whereas with a .125 dial it's 3 turns + 62 on the
dial-----it requires a little more attention). Takes a little getting used
to, and it's where you'll make some scrap initially, but once you've
mastered the dials, it's no big deal, and you can plot holes easily within a
couple thou reliably, assuming your screw is in good condition.

What I do is use a wax pencil and make marks on the saddle/table as
reference points, noting the dial mark at that position. It's especially
important to mark your "0" points, so you can go back to your reference, or
starting points when in doubt. Assuming the screw on your machine is good,
by so marking your machine, you can step off holes time and again, stopping
at the same location without thinking. That's a nice feature if you're drill
ing, tapping, counterboring, or otherwise going back to each location for a
specific function that may not lend itself to being done while you're there
the first time.


A note he Use your (high quality-buy a good one. I recommend a
Starrett
C305R) 6" scale for every move. It will tell you if you've turned the
handle a turn too far, or even catch a mistake if you transpose some
numbers. Carefully applied, you can read a scale to .005" without
much
difficulty. That will save you tons of trouble. It is especially
important when you're stepping off holes, where you have a multitude of
chances of making scrap. Use the scale until it becomes routine,
just
like working with backlash. Touch your spotting drill or center drill
to
the piece, and measure the dimension from your reference point. It
takes a
moment to do, but far less time than making a new part. You'll
improve
your quality immensely if you follow this advice.

No argument here; it makes sense. With the ER set, the changes involved
would not be all that time consuming, and it beats starting over.

Re the edge finder, I think I get it now, at least for edges. I flipped
the belts, and fiddled with a little more speed. I saw definite lateral
movement, and then realized that the motion was smaller than I was
expecting. Now that I know what to look for, I can see it at the speed
I was using before. I have yet to set the dials to check for
repeatability, but will try that next.

Bill

Each edge finder seems to have its own personality, at least those I've
used. Yours appears to be no different. I think you're on the right
track by trying it at various speeds, even if you see it with each one
tried. One of them will be more "clean" than the others. Won't take you
long to figure it out. When you find the magic number, you'll notice it's
more reliable than the others, tending to be more sensitive.

Sounds like things are coming together for you. Can't tell you how nice it
is to share my experience with someone that is willing to learn instead of
challenging each and every comment. You've been a pleasure.

Harold