Got done running the first sucessful set for Brett, thought others might be interested in the progress of the project as well.
lol, so the hold downs I was running turned out to be woefully ineffective. there are vacuum channels under the part that have been more than enough on past materials, but this was my first time with steel. yeah, I'm going to need something a little tighter.
What I found when I came in today:
haha, the program takes ~5 hours to run, and I didn't feel like waiting till 1 am to watch it. the peices broke vacuum and moved around on the final pass. live and learn. good thing its free.
What I should have seen:
and what all the movement caused:
Nice big chunk taken out of one of them.

ok, so now it will get its own hold down plugs cut out, and the next set will be locked into place mechanically before milling starts. there are 4 drilling cycles (4 different hole sizes.) so I'll use those holes to lock the peice down to the table in the future.