On 2011-06-15, Jon Elson wrote:
On 06/15/2011 07:53 AM, Ignoramus10056 wrote:
It took about an hour, but I am finally done, trammed it with a dial
indicator. 0.001" over about 4 inches. (diameter of the circle that
the indicator makes when attached to spindle).

i
The scheme I used is to use a CNC program to mill a shallow circular
groove in a piece of scrap about as large as the machine can reach.
On your machine, it might be about a 10" diameter circle. I position
the spindle back to the center of the groove. Then, I mount
a dial indicator on an arm and sweep the groove. Because my ways are
worn, I get a bit of a saddle-shape, ie. a hump in one axis and a valley
across the other. I try to straddle all these variations when tramming.
This aligns the spindle to the XY plane of motion, not just to the
surface of the table.

Tramming your head is probably harder than mine.

Jon

Jon, I wonder if a circle, milled on a moving table, represents a true
reference surface, or not. I used the top of the Kurt vise as a
reference surface.

It was not "really hard", like changing a transmission on a car on a
hot day, but after a while I hit a virtual wall and could not improve
beyond 0.001" over 4 inches swing.

i