robostang; the cost to us is $0, so it’s a great deal! They were done in a day.
Qbranch and StudmanDan; We don’t have an in house CNC, just a mill and lathe. However, our local community college where we work (along with 330 and 2150) has several, we could have cut them there.
However, we actually asked our sponsor, Northrop Grumman: Space Technology, to cut them for us. I intern there as well so it makes for easy access to shops. Just in my area there are 10+ various machine shops with at least 5-6 CNCs, but often have more. They cut parts for sattelites, so they are used to holding things that you wouldn’t think you can hold.
So, The material was cut from block scrap aluminum (anything not brand new is scrap, it’s not worth their time to re-square stock to cut it. Even the four 38"x5" 3/8" plate for our base) during the night shift; On nights only 1/2 the machines are manned so the machinists sets up his NG job, then does ours while the NG work is cutting.
I just talked to the shop, they actually added an operation in. They clamped a square block and did all the face work (ended up looking like these](http://www.chiefdelphi.com/media/photos/26619)). They then flipped it over and clamped it in soft jaws and faced it to the correct thickness. Then they put in on the lathe and cut the tread groove.
As for them being too thin, we used the same thicknesses on last years wheels and they worked out just fine. If there are any issues, we’ll just beef it up slightly before we cut the ones for the season (before any one says anything, that will happen during the season). The way I CADd it allows us to change the thicknesses and have everything change to match it, so it’s no issue.
Thanks for the input everyone.