On 2008-04-04, The Davenport's wrote:
Dare I ask how to do
precision setups on it?

With toolmaker's buttons. You start on a surface plate and
scribe two intersecting lines at the location of the center of your
desired feature. The drill and tap it for the screw which comes with
the toolmaker's buttons.

What I always found to be a much faster way was to use a combination
drill/countersink on the location of the feature and use a spring center to
indicate the location off of that.

You mean what is sometimes called a "pump" center? It might be
that you can't be as precise on such holes as you can using a height
gauge (set to gauge blocks) and surface plate to position the buttons.
But yes, the pump center in a center hole can do a good job if the
maximum precision is not needed, and be a lot quicker to set up, too.

I will readily grant and acknowledge that the toolmakers buttons let you
adjust AFTER the hole is created, if you have good dials or a good readout
on your mill, you really shouldn't NEED do adjust the buttons

But if you are doing layout on a complex casting, you probably
can't do the initial holes with a mill (or even a jig borer for greater
precision). Usually, all the holes are laid out relative to a reference
surface which rests on the surface plate. Granted, most hobby
metalworkers won't be working on such large castings most of the time.

Enjoy,
DoN.

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