Adapters and mirrors

This is what has been driving us nuts for the past week. Do any of you remember how worried I was that we did not install the mirrors in Italy?

Well, it has come back to bite us. Both the mirrors are supposed to have these precision machined sockets that accept stainless steel adapters used for adjusting the mirror position and allowing for contraction. They problem is that it is supposed to be a tight fit, and as you should know by now, if you need a tight fit, both parts have to be in the same place during machining.

Well, the adapters were made in one shop, and the mirrors in another, so the parts were never test fit. To make matters worse, the walls of the sockets are not very nice, with casting defects and bit chatter.

We sent Hans back to UCSD to pull of an emergency machining job on Saturday night. We got word from Eric that he wanted no more than a 0.005" clearance, so we had to measure each socket with an inside micrometer. If you have ever tried to do this, you will know that it is darned hard to do. After Daniel spent a couple of hours at it, the Vertex guys suggested another technique and I was basically able to reproduce Dan's results. You can see from the photo that the sockets are not very circular. We will probably have to shim to make the difference, we wont know how bad we are until tomorrow.

This is Brian going over the secondary sockets. They were not as bad as the primary, but they are still not circular.










If you want to freak me out, you should bring a grinder near the primary. The sockets on the primary are bad enough that we had to grind down some spots with a die grinder. Al was really good at this, but I had trouble getting into the crack to get out a little ledge that each socket has. We will not know if it is good enough until tomorrow.





Hans is back tonight witht he parts, so we will learn a lot tomorrow.