Then I ran of each of the little 303-ss blocks, which all have been previously machined to .3125 +- .001, and have .126" dia reamed holes.
The spindle was running at maximum RPM (1875 on my mill), and there was little effort required to swing the part next to the endmill. I found that roughing it down to the last .002, and then blowing the chips away from the stop pins and then climb milling the last .002 gave the part a nice finish!
Then It became obvious that I needed to undercut the fixture about .025 smaller radius, so that I could get my little jewlers screw drive blade under the finished part to pop it off the pin!
Then I noticed the pin was tighter on some parts than on others, so I dismanteled the fixture, removed the 1/8 locating pin, and ground a small flat on either side of the pin. this helped compensate for any location error in the holes, and the remaining diameter of the pin would ensure the radius was centered on the hole!