In article ,
F. George McDuffee wrote:

On Wed, 18 Jul 2007 23:02:22 -0400, Joseph Gwinn
wrote:

I don't have any problem getting the wiggler needle to settle on axis.
The problem is seeing *exactly* where the point is with respect to a set
of scribed lines and/or a punch dimple. It takes forever, lots of
fiddling, and sometimes fails, yielding misplaced holes.
=========
Invest in a binocular magnifier, possibly with the auxiliary
magnifier loop.

for an example see
http://www.use-enco.com/CGI/INPDFF?P...PARTPG=INLMK32
this 1_3/4 to 2_3/4 power that can be boosted to
about 18-25$US. Cheaper ones are available but the optics are
not so good and you will get a headache after wearing/using for a
while in my experience. These are not that expensive and will
make a world of difference.

I have one of these (by some brand), with glass lenses. It works well,
but it's too clumsy to work on the mill table. I've tried.


Also try getting more light in your
work area. For some reason many home shop machinists fail to get
enough light.

Yep, got that. I put a fluorescent fixture on the ceiling right next to
the mill, and a gooseneck machine light on a nearby wall, shooting
sideways and down at the business end of the endmill in arbor. It helps
a lot, but still there are many contortions needed, and if the light
isn't just right, it's hard to see both the scribed lines and the
wiggler needle point at the same time.


You may find this of interest
http://littlemachineshop.com/product...=2604&category
=
(I don't have one)

Nor do I. I gather from other comments that such laser edge/center
finders do work well, but are somewhat less accurate than other methods.
Although the accuracy is adequate for most HSM applications.


For center/prick punching locations from scribed lines get a
punch with a magnifier. If you are using a coax indicator you
just need a light prick punch mark, and you will damage the
special punch with the Skidmore unit if you give it a mighty
blast with a heavy hammer.
I like the cross hair type
click on
http://www.skidmoreengineering.com/i...s/Page1171.htm
this has a magnetic base which helps when using on steel.

I have one of these, made by Fowler. It works very well, and I use it a
lot. It has a dot and ring, not a crosshair.

It is not useful for lining mill spindles up, though.


there are also some that use a plastic magnifier.
http://www.productsusa.com/howtouseom.html

The Fowler unit looks like this.


also see
http://store.flexbar.com/merchant2/m...tore_Code=FLX&
Product_Code=14517&Category_Code=Center-Punch

As does this, although the Fowler unit came with only one magnifier and
one punch, and cost $47 (if memory serves).


I'm leaning towards the Enco Fine centering Scope, I think. The key
seems to be vision and reduced contortion. I also liked the suggestion
that one could use it with a DRO on the mill as a largish toolmaker's
microscope.


DRO. I'm in the process of installing a 3-axis Jenix DRO on the
Millrite MVI. I have the X (side-to-side) scale installed, and am
working on the Y (in-and-out) scale. X was easy, because there are
machined parallel surfaces to attach to. Y is harder, as only half the
machined surfaces are available. Z will be a bear, as nothing is flat
and nothing is parallel.


Joe Gwinn